Buffer State Research Articles

Lightweight high-throughput true random number generator based on state switchable ring oscillator

True random number generators (TRNGs) perform an extremely critical role in cryptographic algorithms and security protocols, scientific simulation, industrial testing, privacy protection, and numerous other domains. Nevertheless, modern TRNGs have difficulty striking a reasonable balance between high throughput and low hardware consumption. In this paper, a novel lightweight high-throughput TRNG based on state switchable ring oscillators (SSROs) is proposed. Under the effect of flip-flops that are prone to entering the metastable region, the SSROs randomly switch between oscillatory and buffer states to create jitter and metastability. A feedback strategy is adopted to effectively eliminate the fixed point in the circuit, which further enhances the randomness of the structure. The proposed TRNG is implemented on Xilinx Artix-7 and Kintex-7 FPGAs, with support for automatic routing. It achieves a throughput of up to 400 Mbps while consuming only 16 LUTs and 13 DFFs, showing extremely high resource utilization efficiency. Experimental results show that the output random sequence passes the NIST SP800-22 test, the NIST SP800-90B test, and the AIS-31 test without any post-processing, exhibiting strong robustness against voltage and temperature variations as well as frequency injection attacks.

Cross-Layer Routing Protocol Based on Channel Quality for Underwater Acoustic Communication Networks

Due to the physical characteristics of acoustic channels, the performance of underwater acoustic communication networks (UACNs) is more susceptible to the impacts of multipath and Doppler effects. Channel quality can serve as a measure of the reliability of underwater communication links. A cross-layer routing protocol based on channel quality (CLCQ) is proposed to improve the overall network performance and resource utilization. First, the BELLHOP ray model is used to calculate the channel impulse response combined with the winter sound speed profile data of a specific sea area. Then, the channel impulse response is integrated into the communication system to evaluate the channel quality between nodes based on the bit error rate (BER). Finally, during the selection of the next hop node, a reinforcement learning algorithm is employed to facilitate cross-layer interaction within the protocol stack. The optimal relay node is determined by the channel quality index (BER) from the physical layer, the buffer state from the data link layer, and the node residual energy. To enhance the algorithm’s convergence speed, a forwarding candidate set selection method is proposed which takes into account node depth, residual energy, and buffer state. Simulation results show that the packet delivery rate (PDR) of the CLCQ is significantly higher than that of Q-Learning-Based Energy-Efficient and Lifetime-Extended Adaptive Routing (QELAR) and Geographic and Opportunistic Routing (GEDAR).

Probing-aided spectrum sensing-based hybrid access strategy for energy harvesting CRNs

To address the issues of energy supply and spectrum scarcity in Internet of Things (IoT), energy harvesting (EH) and cognitive radio (CR) technologies have been proposed and widely applied. In EH-CR networks (EH-CRNs), miss detection causes significant energy and time wastage of IoT devices, especially secondary users (SUs), and causes serious interference to primary users (PUs). To alleviate this concern, we propose a probing-aided spectrum sensing (PaSS) model for EH-CRNs, where M pairs of PUs and one pair of SUs coexist. The secondary transmitter (ST) harvests energy from the radio frequency (RF) signals of PUs for opportunistic spectrum access. In the PaSS model, probing operation is employed to further confirm the real state of the spectrum that has been sensed as free in order to avoid the waste of time and energy resulting from miss detection. Based on the PaSS model, we propose a novel hybrid access strategy, where the ST’s actions (i.e., sensing, probing, EH, underlay/overlay transmission mode) depend on the belief vector of M channels, energy state and data buffer state of the ST. By developing an adjusted double deep Q-network (ADDQN) reinforcement learning algorithm, we aim to find the optimal strategy that minimizes the long-term average number of packet losses (ANPL) and the ANPL minimization problem is an integer programming problem. Simulation results validate the ANPL performance of the ST in the ADDQN-PaSS model, and reveal impacts of network parameters on the performance of the ST, and find that at least 7.9% reduction of ANPL is achieved by using the ADDQN-PaSS model.

Quantitative redox measurements for hydrothermal experiments conducted in cold-seal pressure vessels

The cold-seal pressure vessel (CSPV) is a commonly-used apparatus for hydrothermal experiments performed at crustal temperature (T)–pressure (P) conditions. The redox states of the samples in CSPV hydrothermal experiments are normally controlled by the pressure medium, by using oxygen buffers, or with the Shaw membrane technique. Although these techniques have been widely used, the actual redox states of the samples are not necessarily the expected values and need to be quantitatively measured. In this study, by using CoPd, NiPd, and (NiMn)O redox sensors, quantitative redox measurements have been conducted in H2O-pressurized Ni-superalloy (Inconel 713 LC) CSPVs at 700–800 °C and 200 MPa. Oxygen fugacities (fO2) of the H2O pressure medium in three CSPVs used in this study were measured, and their log fO2 values were − 13.11 ± 0.06 (Ni–NiO (NNO) + 0.7), − 13.05 ± 0.06 (NNO + 0.8) and − 12.68 ± 0.07 (NNO + 1.1), comparable with those reported previously. By placing an open capsule containing Ni powder below the sample capsule, the fO2 of the H2O pressure medium can be adjusted to reach that of the NNO buffer (NNO to NNO + 0.2). For the MnO–Mn3O4, Ni–NiO, and Co–CoO oxygen buffers, a steady-state fO2 was always achieved for each buffer at a fixed P-T condition. Measured log fO2 values for the Ni–NiO and Co–CoO buffers are in good agreement with theoretical values calculated from thermodynamic data and also with previous results obtained from vessels pressurized with Ar. The log fO2 values determined for the MnO–Mn3O4 buffer, about 0.3 log unit lower than the theoretical values, are consistent with previous values obtained from vessels pressurized with Ar. These results suggest that the use of H2O pressure medium would not perturb the equilibrium redox states of the oxygen buffers. In addition, we developed a miniature sensor that is small enough to be loaded together with other sample material, allowing the monitoring of fO2 in actual experiments.

Optimized Probabilistic Sink Node Deployment for Enhanced Performance in Wireless Sensor Networks

This paper presents an innovative mechanism to deploy sink nodes in Wireless Sensor Networks (WSN), which play an essential role in the gathering sensed data from sensor nodes across diverse applications. Our mechanism is different from existing mechanisms, which deploy sink nodes based on the residual status of buffer and energy of the sensor nodes. Instead, proposed mechanism’s sink node deployment is decided based on the optimal probabilistic metrics related to buffer and energy status during data processing; aim to extend the network performance with respect to risk of buffer overflow and energy consumption. We analyse and validate the performance of the proposed work through simulation and compared the results with existing residual-based sink node deployment mechanisms. The results indicate the signification extension in the performance in terms of energy, packet loss and lifetime by mitigating bottlenecks at nodes. The work contributes to the improvement of WSN design and deployment mechanisms by significantly enhancing the performance and reliability of the network.

The Significance of Nepal’s Geopolitical Location; Reality Checking

This research paper investigates Nepal's geostrategic importance by analyzing its role as a significant nexus in South Asia. In ancient times, Nepal occupied a crucial geostrategic position as it served as a pivotal crossroads connecting South Asia, Tibet, and China, facilitating the exchange of commodities, ideas, and culture. The central argument posits that Nepal's geographic location endows it with substantial strategic significance, both politically and economically, enabling it to influence regional dynamics. Employing a mixed methodology, the research delves into various facets of Nepal's geostrategic relevance through historical assessments, geopolitical analyses, and case studies of hydro-politic potentiality. The approach commences by examining Nepal's historical role as a buffer state amid regional powers, leading to a longstanding history of diplomatic struggles to safeguard its sovereignty. Furthermore, the paper explores how Nepal's geographical position shapes its security dynamics, particularly in the context of the escalating China-India rivalry in contemporary times, employing geopolitical frameworks to illuminate this aspect. To shed light on Nepal's involvement in facilitating global trade and connectivity, the methodology also includes case studies of infrastructure initiatives such as the Belt and Road Initiative and regional connectivity projects. In conclusion, the paper asserts that Nepal's geostrategic significance is a product of its historical development and proactive international relations, closely intertwined with its geographic positioning. It underscores Nepal's potential to serve as a conduit for regional cooperation and economic integration while emphasizing the need for astute navigation to preserve its independence in a challenging geopolitical landscape.

Joint optimization of condition-based maintenance policy and buffer capacity for a two-component self-repairable serial system

This paper investigates a self-repairable serial system with two components and a buffer. Competitive failure processes are considered due to the internal degradation and external shock processes of components. The system reliability is calculated based on the integration of the internal degradation process and external shock process. When one of the components deteriorates to the PM or CM thresholds, it is restored to an imperfect state under dynamic time limitations based on the previous internal degradation and external shocks. As for the other component, it needs to be repaired or not according to the reliability of the component; it needs to be shut down or not based on the buffer status and the allocation of the component in the system. The optimal initial buffer capacity setting and PM threshold at minimum cost are found by minimizing the system's total cost in a given running cycle. Finally, numerical and case studies are provided to demonstrate the feasibility and superiority of the presented model.

Strategic Gateway: Mongolia's Perplexing Challenges

Mongolia, a vast country with a crowded capital, faces economic recessions, poverty, unemployment, corruption, and infrastructure deficiencies, exacerbated by extreme weather conditions owing to its geographical location. Despite its recent sovereignty, self-sufficiency remains elusive. Cultural, historical, territorial, and political ties to neighbours offer advantages but entail dependence on Russia and China. Adjacent to Russia, a regime with invading potential, Mongolia faces the risk of attacks, but the presence of China acts as a short-term protective measure. Although China recognizes Mongolia as an independent country, it has a habit of claiming historical lands. Mongolia exists as a sovereign state predominantly because both Russia and China consider it a buffer state. Changes in Russo-Chinese dynamics could lead to Mongolia’s absorption into China or it becoming a battleground for warfare. Despite being landlocked, Mongolia holds strategic significance in the maritime domain as an alternative trade route to China if the Malacca Strait is ever to be choked, though with minimal economic gains. Thus, Mongolia's significance as a remedy to a chokepoint is juxtaposed with its vulnerability to regional political tensions. To strengthen its foreign policy, Mongolia has sought to balance relations and establish partnerships with global powers outside its immediate neighbourhood.

THE ROLE OF AFGHANISTAN IN CENTRAL ASIA: RISKS AND FUTURE PROSPECTS OVERVIEW

In the International landscape Afghanistan encompasses a faltering polity with several arguments that support this claim. The state is known as the buffer state and a landlocked country, which is currently under the umbrella of the Taliban regime. The Central Asian Countries are specifically apprehensive and nervous regarding the uncovered system in Afghanistan, notably considering the withdrawal of international powers in 2014 and then in 2021. Central Asia exemplifies an intricate interplay of risks, challenges, and future. Similarly, this research paper highlights the geopolitical landscape of Afghanistan within the context of Central Asia, emphasizing both the current risks and potential opportunities for the region’s prospects. Besides, it also investigates the challenges and critical rebukes of modern international relations in Central Asia, while exploring avenues for the progress of the scenario examined in the proposed study. However, the researcher employed a descriptive method of inquiry, collecting secondary data from meritorious journals. The research study would be wholesome in analyzing alternatives of Afghanistan and Central Asian ties addressing regional challenges for modern international relations. Thus, the researchers would base new avenues for upcoming related domains in scholarly research. In this way, the present study is limited to investigating Afghanistan in central Asia, navigating its influence with the risk and prospects. It plays a key role in underscoring Afghanistan’s new journey with the Taliban, which aims to globalize the world under new leadership.

STOP: Joint send buffer and transmission control for user-perceived deadline guarantee via curriculum guided-deep reinforcement learning

Real-time applications with strict user-perceived deadline requirements, such as cloud virtual reality (VR) gaming and high-frequency trading, have experienced substantial growth in recent years. To ensure the user-perceived deadline at the transport layer, i.e., the network transmission delay and the waiting delay in the send buffer, transmission control scheme plays an important role. While several delay-sensitive transmission control schemes have been proposed, none of them consider the impact of waiting delay in the send buffer. To address this issue, we propose STOP, a joint send buffer and congestion window (CWND) control approach for guaranteeing user-perceived deadline via curriculum-guided deep reinforcement learning. To obtain optimal joint control policy, STOP utilizes a reinforcement learning-based algorithm to jointly adjust the CWND and send buffer with respect to the send buffer state, the network condition and the deadline requirement. Furthermore, to enhance the generalization capability of reinforcement learning-based algorithm, STOP incorporates curriculum learning during the training phase with a difficulty measurer and training scheduler. Extensive experiments in NS-3 indicate that the STOP scheme achieves an overwhelmingly higher average arrival ratio, i.e., around 95% vs. around 0.2%, compared with current prevalent transmission control scheme such as BBR, Cubic and Vegas.

Neural Network Based Rate Control for Versatile Video Coding

In this work, we propose a neural network based rate control algorithm for Versatile Video Coding (VVC). The proposed method relies on the modeling of the Rate-Quantization (R-Q) and Distortion-Quantization (D-Q) relationships in a data driven manner based upon the characteristics of prediction residuals. In particular, a pre-analysis framework is adopted, in an effort to obtain the prediction residuals which govern the Rate-Distortion (R-D) behaviors. By inferring from the prediction residuals with deep neural networks, the Coding Tree Unit (CTU) level R-Q and D-Q model parameters are derived, which could efficiently guide the optimal bit allocation. Subsequently, the coding parameters, including Quantization Parameter (QP) and λ, at both frame and CTU levels, are obtained according to allocated bit-rates. We implement the proposed rate control algorithm on VVC Test Model (VTM-13.0). Experimental results exhibit that the proposed rate control algorithm achieves 0.77% BD-Rate savings under Low Delay B (LDB) configurations when compared to the default rate control algorithm used in VTM-13.0. For Random Access (RA) configurations, 1.77% BD-Rate savings can be observed. Furthermore, with better bit-rate estimation, more stable buffer status can be observed, further demonstrating the advantages of the proposed rate control method.

Effects of shear strain on HZO ferroelectric orthorhombic phases

The stabilities of hafnium and zirconium oxide ferroelectric orthorhombic phases, oIII-phase (Pca21) and oIV-phase (Pmn21), under shear strain are investigated theoretically by atomic modeling with density functional theory calculations. The results indicate that oIV-phase serves as a buffer state preventing oIII-phase from transforming into m-phase (P21/c) under structural distortion caused by shear strain and meanwhile preserves the remanent polarization to some certain degree. Shear strain will also induce the reduction in coercive field of the HZO film due to the distortion of oIII-phase or phase transition into oIV-phase. It is very possible to identify oIV-phase with careful analysis of high-resolution transmission electron microscopy and high-angle annular dark-field STEM images at the region having a crystal tilt angle smaller than 86°.

Trusted Collaboration for MEC-Enabled VR Video Streaming: A Multi-Agent Reinforcement Learning Approach

Collaboration among mobile edge computing (MEC) has been envisioned as a promising paradigm to meet the requirements of wireless virtual reality (VR) applications. However, trust risks create tremendous challenges in MEC collaboration due to the distributed, complex, and unreliable nature of resource providers. In this paper, we present a trusted collaboration framework for VR video streaming to manage the video buffer in VR devices (VDs) under a more realistic distributed environment. In the framework, the rendering tasks can be processed collaboratively among edge servers (ESs) by exploring their behaviors (e.g., selfish behavior, malicious behavior, and cooperative behavior). Considering the collaborator may not be fully trustworthy, we present a novel trust evaluation method by combining direct and indirect values, aiming to ensure reliable collaborator selection. Then, we formulate an optimization problem to maintain an effective buffer state in VR devices (VDs) through jointly optimizing collaborator selection, spectrum allocation, and rendering resource allocation. Due to the fluctuating wireless fading channel and the dynamic video rate, the optimization problem is intractable by adopting traditional methods. Then, we adopt the multi-agent deep deterministic policy gradient (MADDPG) to tackle this dynamic and distributed problem. Simulation results indicate that the proposed approach can achieve a good performance.

Primorsky Musical Institute in the history of the development of academic music in the Far East (1923-1924)

The article examines the activities of the Primorsky Musical Institute (1923-1924), which contributed to the development of academic music in the Far East in the post-revolutionary period, associated with the liquidation of the "buffer state" of the Far Eastern Republic (FER, 1920-1922) and its accession to the Russian Soviet Federative Socialist Republic (RSFSR). Through the prism of historical documents and archival materials, the factology of which did not fall into the analytics available today, corrective information is introduced into music science, which, on the one hand, forms an up-to-date view of the activities of the Primorsky Musical Institute, in terms of preserving traditions, paying attention to successive ties with the Imperial Russian Musical Society (RMO / IRMO), which played a special role in organizing the musical life of the country, and the Far East during the period of Imperial Russia. On the other hand, he names the reasons why the closure of the Institute led to the impossibility of the historical continuation of the forward line of development laid down by the IRMS in the Sovietized post-FER period. Contextual study allows the fact of the emergence of the Primorsky Musical Institute in Vladivostok to be comprehended as a consequence of the inertially preserved organizational work of the Vladivostok branch of the IRMO (1909-1917), which opened a music school at the Department, and then established a music school at the RMO (1917-1922).

Improving the Timeliness of Two-Source Status Update Systems in Internet of Vehicles With Source-Dedicated Buffer: Resource Allocation

Age of information (AoI) is a pertinent metric for characterizing the timeliness of status updates in Internet of Vehicles (IoV). Resources allocated to update transmission would significantly affect the timeliness of status update observed at the receiver end. This work investigates the sum average AoI of a two-source wireless updating system in IoV by modeling the system as a non-preemptive queue with a size-two source-dedicated buffer. Two bandwidth allocation schemes, i.e., an asynchronous time division multiplexing (ATDM) scheme and a dynamic bandwidth allocation (DBA) scheme, are proposed for the system. In the ATDM scheme, status updates are transmitted using all available bandwidth sequentially while in the DBA scheme, the server fractionally allocates the available bandwidth for transmitting the arrived update based on the buffer state. By analyzing the age evolution of each update stream based on stochastic hybrid systems, the closed-form per-source average AoI and the sum average AoI of the two proposed schemes are derived. In particular, the per-source average AoI when the system provides priority for serving one update stream is also given. It is demonstrated that by employing the ATDM scheme and the DBA scheme with optimized bandwidth allocation factor, the system can achieve a significant improvement in terms of sum average AoI, enhancing the update freshness.

Differential Modulation-Based Buffer-Aided Cooperative Relaying Network

In this article, we consider a multirelay cooperative network using a differential modulation technique. The given set-up consists of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$K$</tex-math></inline-formula> decode-and-forward (DF) relays, each equipped with a buffer of size <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$L$</tex-math></inline-formula> . All transceiver nodes in the considered cooperative network apply differential modulation for the transmission of data, hence, channel-state information is not required for decoding of the data at the receiving nodes. A priority-based max link selection approach is used for the selection of the best links for the transmission and reception of data. The Markov chain approach is used to derive the state-transition matrix of the system, which is then further used to model the evolution of buffer status. Analytical expressions of the outage probability and average bit error rate are obtained with the help of the state-transition matrix. The performance of the considered system is analyzed for different buffer sizes and a number of relays. The performance is then further compared with that of a coherent buffer-aided network and also with the nonbuffer-aided differential amplify-and-forward and DF systems. As compared to the coherent buffer-aided network, the considered buffer-aided differential system suffers a negligible signal-to-noise ratio penalty in the scenario when more than one buffer-aided relay is present in the network, which is a significant improvement when compared with the nonbuffer-aided differential cooperative systems, which suffer a performance penalty of approximately 3 dB as compared to their coherent counterpart.

Novel Data Transmission Schemes for Inter-WBAN Networks Using Markov Decision Process.

This work proposes a stochastic model of the coordinator units of each wireless body area network (WBAN) in a multi-WBAN scenario. In a Smart Home environment, multiple patients can come into the vicinity of each other while each of them is wearing a WBAN configuration for monitoring body vitals. Thus, while multiple WBANs coexist, the individual WBAN coordinators require adaptive transmission strategies in order to balance between maximizing the likelihood of data transmission and minimizing the chances of packet loss due to inter-BAN interference. Accordingly, the proposed work is divided into two phases. In the offline phase, each WBAN coordinator is modeled stochastically and the problem of their transmission strategy has been modeled as a Markov Decision Process(MDP). The channel conditions and buffer status that influence the transmission decision are taken to be the state parameters in MDP. The formulation is solved offline, prior to deployment of the network to find out the optimal transmission strategies for various input conditions. Such transmission policies for inter-WBAN communication are then incorporated into the coordinator nodes in the post-deployment phase. The work is simulated using Castalia and the results demonstrate the robustness of the proposed scheme in handling both favorable and unfavorable operating conditions.

A Novel Link Selection in Coordinated Direct and Buffer-Aided Relay Transmission

Buffer-aided relay networks provide more reliability and coverage in future wireless communications. Therefore, this paper investigates a buffer-aided cooperative relaying system with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> relays and a direct link from the source to the destination, providing a general scenario different from other existing state-of-the-art techniques. In particular, we propose a novel link selection scheme, which adaptively coordinates the selection priorities of the direct and cooperative relay link according to the instantaneous buffer state. The performance of the proposed link selection scheme is analyzed, in terms of outage probability, average packet delay (APD) and diversity order by providing closed-form expressions. For asymptotic analysis, a theoretical framework is presented by dividing all buffer states into different sets, which verifies that the minimum buffer size is just two for achieving the full diversity order of 2 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> + 1. We also provide the relationship between the asymptotic APD and diversity order by adjusting predefined target queue lengths, which shows that the diversity order ranges from <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> + 1 to 2 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> + 1 as the asymptotic APD ranges from 0 to <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> time slots per packet. Both theoretical and simulation results demonstrate that direct transmission significantly improves the outage and delay performance simultaneously.

Examining the status of CPU working load, processing load and controller bandwidth under the influence of packet-in buffer status located in Openflow switches in SDN-based IoT framework

Examining the status of CPU working load, processing load and controller bandwidth under the influence of packet-in buffer status located in Openflow switches in SDN-based IoT framework

Lips and Teeth: China’s Buffer Thinking Toward North Korea

ABSTRACT Chinese officials characterize the bilateral relations between China and North Korea as ‘lips and teeth’ at times and most China scholars would also agree that North Korea is China’s buffer state. Despite the popularity of accepting this ‘buffering relationship’ between the two countries, few scholarly works explain this relationship in depth. What does ‘China regards North Korea as a buffer state’ mean? When and under what conditions did the Chinese Communist Party (CCP) leaders begin to view North Korea as a buffer state? Most importantly, how did such a buffer view shape China’s behavior when North Korea’s existence was endangered? The purpose of this article is to shed more lights on this unique geopolitical relationship forged in blood. It argues the CCP leaders’ first view on the Korean Peninsula was nationality minority. It was the Korean War that fundamentally changed the way the leaders perceived the value of the peninsula, from a non-geopolitical to a geopolitical one—North Korea is a buffer state keeping a hostile force away from the Sino-North Korean border. Evidently, China’s buffer thinking toward North Korea was one key factor contributing Chinese military and diplomatic protection over North Korea during the first North Korean nuclear crisis.