Transmission Channel Research Articles

A Higher Performance Data Backup Scheme Based on Multi-Factor Authentication.

Remote data backup technology avoids the risk of data loss and tampering, and has higher security compared to local data backup solutions. However, the data transmission channel for remote data backup is not secure, and the backup server cannot be fully trusted, so users usually encrypt the data before uploading it to the remote server. As a result, how to protect this encryption key is crucial. We design a User-Centric Design (UCD) data backup scheme based on multi-factor authentication to protect this encryption key. Our scheme utilizes a secret sharing scheme to divide the encryption key into three parts, which are stored in the laptop, the smart card, and the server. The encryption key can be easily reconstructed from any two parts with user's private information password, identity and biometrics. As long as the biometrics has enough entropy, our scheme can resist replay attacks, impersonation user attacks, impersonation server attacks, malicious servers and offline password guessing attacks.

Enhanced Non-Orthogonal Multiple Access Performance Using Channel Coding for High-Altitude Platform System (HAPS)

The high-altitude platform system (HAPS) is a promising technology for providing high-speed data transmission and coverage for remote areas. Still, it suffers from unpredictable channel transmission, especially in the Rician channel. To overcome the issue in transmission, we used one channel coding strategy, namely the quasi-cyclic low-density parity-check (QC-LDPC). This study aims to evaluate the performance of power domain non-orthogonal multiple access (PD-NOMA), which allows multiple users to share the same spectrum in a downlink communication system from HAPS to three ground stations. We simulated the system using MATLAB simulation with different power allocation coefficients for every ground station. The simulation results showed that QC-LDPC codes can significantly lower the signal-to-noise ratio (SNR) required to achieve the same bit error rate (BER) as uncoded NOMA, especially in scenarios with uneven power allocation. The average improvement of QC-LDPC over uncoded NOMA was 8.4% in SNR. However, we also observed that NOMA is prone to domino errors, where decoding errors in one ground station can propagate and degrade the performance of the subsequent ground station. Furthermore, we found that power allocation significantly impacts the system performance, while the location and power allocation of the second ground station have a minor effect. Based on these findings, we conclude that QC-LDPC can enhance system performance in scenarios with low received power and that power allocation is a crucial factor for NOMA systems with multiple ground stations.

Monetary Policy Transmission in Canada – A High Frequency Identification Approach

Abstract I study the effects of monetary policy shocks in Canada on economic and financial variables. With a narrow window around a policy announcement, I create a new set of intraday level, high-frequency monetary policy surprises using the three-month Canadian Bankers’ acceptance rate futures. I use this measure to identify monetary policy shocks as an external instrument in a monthly VAR. Following a 25 basis point contractionary policy shock, I find that the decline in output is more powerful and peaks earlier than previous empirical works show, with a peak decline of 0.5 % points after 18 months. Price level declines are similarly more powerful and earlier, reaching a decline of 0.3 % points after 24 months. In addition, increases in the credit and mortgage spreads indicate the presence of a domestic credit channel of monetary policy transmission for Canada. Finally, I show that the surprise measure is robust to information effects.

Security-based low-density parity check encoder for 5G communication

The fifth generation (5G) of mobile telecommunication standards is intended to offer better performance and efficiency. One of the most significant difficulties in delivering safe data transfer through the transmission channel in the emerging 5G technology is channel-coding security. This research primarily focused on offering information transmission that is secure in the place of novel assaults such as side-channel attacks. In this research, we present a low-density parity check (LDPC) encoder that is constructed using the multiplicative masking method to overcome side-channel attacks, one of the most significant security concerns for the upcoming 5G system. As a result, it offers greater security, reduced complexity, and higher performance. Power, area, and delay can all be calculated using LDPC codes. Comparing multiplicative masking implemented LDPC encoders to ordinary channel coding techniques in terms of security seen that multiplicative masking implemented LDPC encoders offer more security. The program Xilinx ISE 14.7 can synthesize the analysis. The advantage of multiplicative masking is that it offers a promising level of security through the principle of randomization, which is the foundation of the procedure. According to the analysis, the secured transmission of the data by the proposed multiplicative masking implemented LDPC encoder is increased.

Channel assisted noise propagation in a two-step cascade.

Signal propagation in biochemical networks is characterized by the inherent randomness in gene expression and fluctuations of the environmental components, commonly known as intrinsic and extrinsic noise, respectively. We present a theoretical framework for noise propagation in a generic two-step cascade (S→X→Y) regarding intrinsic and extrinsic noise. We identify different channels of noise transmission that regulate the individual and the overall noise properties of each component. Our analysis shows that the intrinsic noise of S alleviates the general noise and information transmission capacity along the cascade. On the other hand, the intrinsic noise of X and Y acts as a bottleneck of information transmission. We also show a hierarchical relationship among the intrinsic noise levels of S, X, and Y, with S exhibiting the highest level of intrinsic noise, followed by X and then Y. This hierarchy is preserved within the two-step cascade, facilitating the highest information transmission from S to Y via X.

Photonic crystal-connected bidirectional micro-ring resonator array for duplex mode and wavelength channel (de)multiplexing

The progress of on-chip optical communication relies on integrated multi-dimensional mode (de)multiplexers to enhance communication capacity and establish comprehensive networks. However, existing multi-dimensional (de)multiplexers, involving modes and wavelengths, face limitations due to their reliance on single-directional total internal reflection and multi-level mode conversion based on directional coupling principles. These constraints restrict their potential for full-duplex functionality and highly integrated communication. We solve these problems by introducing a photonic-like crystal-connected bidirectional micro-ring resonator array (PBMRA) and apply it to duplex mode-wavelength multiplexing communication. The directional independence of total internal reflection and the cumulative effect of the subwavelength-scale pillar within the single-level photonic crystal enable bidirectional mode and wavelength multiplexed signals to transmit among multi-pair nodes without interference, improving on-chip integration in single-level mode conversion. As a proof of concept, we fabricated a nine-channel bidirectional multi-dimensional (de)multiplexer, featuring three wavelengths and three TE modes, compactly housed within a footprint of 80 μm×80 μm, which efficiently transmits QPSK-OFDM signals at a rate of 216 Gbit/s, achieving a bit error rate lower than 10−4. Leveraging the co-ring transmission characteristic and the orthogonality of the mode-wavelength channel, this (de)multiplexer also enables a doubling of communication capacity using two physical transmission channels.

Construction of porous graphene and network carbon nanotubes to develop high-performance and multifunctional carbon fiber composites

Structurally and functionally integrated carbon fiber reinforced polymer composites (CP) are indispensable in electronic devices, where the combination of brilliant mechanical properties, electromagnetic shielding properties and thermal management capabilities are required. Designing and optimizing the interface structure is an effective solution to the above problems. In this work, porous graphene and network carbon nanotubes were successfully integrated into CP. Graphene and carbon nanotubes form a crosslinked structure in which graphene improve the fiber/matrix interfacial bonding and carbon nanotubes enhance the matrix cohesion. Due to their synergistic enhancement, the tensile strength (183.00 ± 5.66 MPa) of graphene and carbon nanotubes reinforced CP (CG-CP) is increased by 65.85 % and the wear rate (1.19 × 10–13 ± 0.05 × 10−13 m3(N·m)−1) is reduced by 74.52 %. Further, the crosslinked structure of graphene and carbon nanotubes creates a high-conductivity and heat-conductive transmission channel, enabling CG-CP to achieve an electromagnetic interference shielding efficiency of up to 48.94 dB in the X-band and 52.62 dB in the Ku-band at a thickness of 0.3 mm, and a 20.98 % improvement of thermal conductivity (0.767 ± 0.002 W(m·K)−1), which simultaneously achieves excellent electromagnetic shielding performance and thermal management capability. The high-performance and multifunctional CG-CP offers a broad prospect regarding the application of advanced electronic devices.

Who bears the costs of inflation? Euro area households and the 2021–2023 shock

We measure the heterogeneous first-order welfare effects of the recent inflation surge across households in the euro area. A simple framework illustrating the numerous transmission channels of surprise inflation to household welfare guides our empirical exercise. By combining micro data and aggregate time series, we conclude that: (i) country-level average welfare costs – expressed as a share of triennial income – were sizable and heterogeneous: around 3% in France and Spain, 7% in Germany, and 9% in Italy; (ii) this inflation episode resembles an age-dependent tax, with the retirees losing up to 14%, and roughly half of the 25–44 year-old winning; (iii) losses were quite uniform across consumption quantiles because rigid rents served as a hedge for the poor; (iv) nominal net positions were the key driver of heterogeneity across-households; (v) the rise in energy prices generated vast variation in individual-level inflation rates, but unconventional fiscal policies helped shield households. The counterpart of this household-sector loss is a significant gain for the government.

A High-Reliability Quantum Communication Protocol via Controllable-Signal Attenuation

Since the protocol for counterfactual quantum communication was proposed, complete counterfactuality can be achieved as there are no physical particles in the transmission channel. However, it relies on some restrictive factors, such as requiring an infinite number of beam splitters and no degradation. We conducted numerical simulations to assess the reliability of quantum communication combined with the actual test environment and found that the inevitable degradation, including component losses or path losses, limits the number of beam splitters. Furthermore, we carried out the experimental simulation of a high-reliability direct communication protocol using the method of controllable-signal attenuation. The peak reliability of μ1=27.6±0.22 that was obtained was much higher than the current communication protocol of the chained interferometer system. The optimized experimental equipment could compensate the system’s balance under various restrictive conditions and make it possible to achieve 100% reliability with imperfect interferometers.

Knowledge Hiding Behavior in Online Learning Communities: A Chain Mediation Based on Self-Efficacy and Organizational Psychological Ownership

With its flexible and convenient learning methods, rich learning resources and convenient information transmission channels, the online learning community has injected new impetus into the cause of education. However, the open and generative characteristics of the online learning community also preclude learning activities from implementing collective constraints, resulting in the emergence of knowledge hiding behavior. Based on this, researchers have attempted to explore the factors that affect knowledge hiding behavior and to identify the influencing mechanisms. Using structural equation modeling (SEM) and exploratory factor analysis (EFA), this study analyzed a questionnaire on the knowledge hiding behavior of 420 graduate students in online learning communities and found that professional commitment, transformational leadership and a proactive personality have a negative impact on knowledge hiding behavior through self-efficacy and organizational psychological ownership. Based on the model interpretation, this paper suggests that the following aspects should be explored for their potential to diminish knowledge hiding behavior: Assess the proactive personality level of graduate students; the training unit can stimulate students’ self-efficacy in terms of the expected results, rewards, relationships and perceived costs of the individual; the supervisor should establish and improve the knowledge sharing mechanism within the organization; the tutor should strengthen the cultural construction of the scientific research team.

TWO-LEVEL CONCEPT FOR SIMULATING UNIFORM INTERFERENCE-RESISTANT DIGITAL DATA TRANSMISSION

The article formalizes, creates and provides for consideration the concept of a single secure interference-resistant data transmission channel. In modern cybersecurity theory and practice, there is the NIST Cybersecurity Framework, which is a set of recommendations for reducing risks for organizations. In order for high-level data to be secure, there are requirements for the SIA triad, namely confidentiality, integrity and availability of information. Therefore, in the future, the expediency of the work and its result will directly depend on the satisfaction of the SIA conditions. As you know, high-level data: such as e-mail, visual data in the GUI of various applications, etc., are transmitted over low-level communication channels: such as cables, wireless radio communication channels, and others. At each of the levels for safe transmission of information, there are specific pests. At high levels, the main threat to information is man and the human factor. The lower the level of information transmission becomes, the more nature, natural obstacles and random short phenomena begin to influence. In order for the user to be able to use various devices without a threat to the confidentiality, integrity and availability of information, it is necessary to actively and continuously develop, improve and improve the existing methods of data protection, restoration, transmission and storage. Each aspect in this struggle for security is both an advantage and a disadvantage: excessive security is not appropriate for mass traffic, complexity does not always provide adequate security, and so on. Therefore, the optimality and expediency of the methods used becomes an important factor. For these reasons, the paper proposes a relatively simple, but no less effective approach to maintaining SIA requirements.

Construction of Ag2O/WO3-based hollow microsphere p-n heterojunction for continuous detection of ppb-level H2S gas sensor

Three-dimensional (3D) hierarchical hollow microsphere WO3 and Ag2O/WO3 heterojunction materials were prepared by a simple hydrothermal method for a highly sensitive continuous response H2S gas sensor. The results show that compared with the original WO3 (Ra/Rg=12.5, 10 ppm, 70℃), the sensor based on Ag2O/WO3 has excellent H2S sensing performance at 60℃. Including ultra-high sensitivity (Ra/Rg=207.12, 10 ppm), continuous detection of different concentrations of H2S gas (0.05–50 ppm), fast response capability (15 s), low detection limit (50 ppb), high selectivity and reliable stability. The study of gas sensing mechanism shows that the synthesized 3D hierarchical hollow microsphere structure provides more channels for gas diffusion and transmission. The dispersion of Ag2O nanoparticles (NPs) on the surface of WO3 provides more reactive sites for gas adsorption. At the same time, the charge transfer is promoted by constructing Ag2O/WO3 p-n heterojunction. Sulfurization of Ag2O improved the response value and selectivity to H2S gas. These factors together determine the superior performance of the prepared Ag2O/WO3 H2S-based sensor.

How does implementing the Extractive Industries Transparency Initiative (EITI) affect economic growth? Evidence from developing countries

Although there is no consensus on the relationship between natural resource abundance and economic growth, much of the economic literature suggests that natural resource abundance negatively affects economic growth in developing countries, leading to the resource curse theory. This situation led the international community to create the Extractive Industries Transparency Initiative (EITI) in 2003 to promote the effective contribution of natural resources to economic growth through a process involving governments, extractive industries, and civil society. Considering 99 developing countries from 1995 to 2019 and applying recent heterogeneity-robust difference-in-differences (DID) estimators, we find a positive and statistically significant relationship between EITI implementation and economic growth. Several robustness checks support this result. Most interestingly, the analysis of EITI’s dynamic effects reveals that these effects occur only in the short and medium terms. In addition, we tested several potential transmission channels and identified the increase in foreign direct investment and the rise in resource revenue as the main transmission channels. Moreover, we postulate and investigate four possible explanations behind the EITI’s mixed results on long-term growth: the lack of evidence of a negative relationship between natural resource abundance and long-term economic growth over the study period, a possible increasing reliance on non-resource taxes, a possible signaling effect targeted by member countries, and the lack of effect of EITI implementation on reducing corruption. Finally, the document provides economic policy recommendations for better governance in the management of natural resources in order to increase their contribution to development financing. Furthermore, improving governance in managing critical minerals is vital to avoid a “new curse of critical minerals”.

Multichannel information transmission via a dual-frequency point space-time coding metasurface

Space-time coding (STC) digital metasurfaces enable dynamic control of nonlinear harmonics. To achieve efficient frequency tuning and harmonic control, we propose a one-bit column-controlled temporal coding dual-frequency point STC digital metasurface. Using a field-programmable gate array (FPGA) to control diode switching, the metasurface is encoded to generate multiple target reflected harmonics as independent information transmission channels. The amplitude intensities of these harmonics are defined as independent binary symbols for transmission. The proposed space-time coding digital metasurface can achieve a phase shift of 180° in its unit structure, with reflectivities above 90% at both operating frequencies. We fabricated the designed metasurface and tested its far-field scattering experimentally. When the incident electromagnetic wave frequency is 4.63 GHz, the predicted results are essentially consistent with the experimental findings.

Quantum conditional entropy and classical-quantum conditional entropy with localization characteristics

In the era of rapid development of quantum mechanics, some issues in the field of quantum information have become increasingly important. Local quantum Bernoulli noises (LQBNs) is a localized Bernoulli functional, and it is the localization of quantum Bernoulli noises (QBNs). The distinctive feature of LQBNs lies in its localization properties, which make it highly valuable in the field of quantum information. In this paper, we study three new types of quantum conditional entropy with localization characteristics from three dimensions: local quantum conditional entropy, local quantum conditional entropy at the same position, and classical-quantum conditional entropy. Based on the locality of LQBNs, we prove that the local quantum conditional entropy is concave and unitary invariant. Surprisingly, we find that the local quantum mutual information (entropy) corresponding to the same position is 0. The local quantum conditional entropy defined based on the local quantum state at a specific position, proposed in this paper, provides new insights into understanding the impact of local quantum noise on the information transmission in quantum channels. This discovery not only deepens our understanding of the internal structure of local quantum entropy, but also reveals its influence on the performance of quantum communication.

Political instability and economic growth: Causation and transmission

This paper examines the link between political instability and economic growth in 34 advanced economies from 1996 to 2020. First, we use a panel VAR estimated via the System GMM to explore the endogenous relationship between economic growth and political instability and identify transmission channels. Second, we employ an instrumental variable approach, exploiting temperature variation and spillover effects of political instability to establish causality. The results of both approaches indicate that a one-standard deviation shock of political instability significantly and substantially reduces economic output. We find no evidence, however, that economic growth affects political instability.

Migrant Remittances and Conflicts in Sub-Saharan African Countries: Effects and Transmission Channels

Migrant Remittances and Conflicts in Sub-Saharan African Countries: Effects and Transmission Channels

Commodity Futures Market Conditions and Climate Policy Risk: Evidence From Energy and Metals Markets

ABSTRACTThis study investigates the impact of climate policy uncertainty (CPU) on energy and metal commodity futures markets by employing quantile regression, which accounts for various (bearish, normal, and bullish) markets. Our results reveal that the impact of CPU shocks is heterogeneous and market condition‐specific. Particularly, CPU exerts a significantly negative effect on all commodities, except natural gas, in a bearish market. Under a normal market, the impact of CPU on energy returns varies across commodities whereas for a bullish market, the CPU effect is mixed. The results also reveal natural gas to be a good hedge instrument for climate policy risk. We further conducted channel analysis using the theory of storage and hedging pressure hypothesis. The key finding reveals inventory level as the transmission channel of climate policy risk. Our findings have implications for the inventory management strategies of producers and suggest that regulators should consider market‐based policies in their decarbonization efforts.

What does housing collateral mean for Hong Kong economy? From the perspective of modelling and policy implication

This paper studies the housing sector of Hong Kong and the role of collateral constraint in modelling Hong Kong economy, through the lens of a small open economy DSGE model with a currency board exchange rate commitment. By estimating and evaluating the model by Indirect Inference over the sample period of 1994Q1–2018Q3, it is found that the collateral model can match data behaviour. Comparing with the tests generated from the model without collateral, collateral model can match the housing price data better, while the model without collateral fits the general price better. Since collateral constraint acts like an additional transmission channel, it enhances the impact from shocks and housing price is highly determined by housing demand. We further investigate LTV policy, finding it could be applied as macroprudential policy, especially when addressing the problem caused by increase in the US interest rate and the burst in the domestic housing demand, but the government should watch closely to the crowding out effect from export to housing demand and housing investment.

Does one (unconventional) size fit all? Effects of the ECB’s unconventional monetary policies on the euro area economies

This paper assesses the macroeconomic impact of ECB’s unconventional monetary policies (UMPs) in the euro area. We show that: (i) the relevance of the transmission channels has changed over time, with portfolio re-balancing becoming more important than the signalling effect after June 2014; (ii) there exists a substantial heterogeneity in the transmission to core and peripheral economies. By leveraging on these findings, we identify UMP shocks in a time-varying SVAR with “dynamic” restrictions and we quantify the macroeconomic impact of ECB’s measures via counterfactual analyses. We find that, absent those measures between 2014 and 2018, output growth would be on average 0.27 pp lower in peripheral countries, whereas inflation would drop on average by 0.2 pp in core economies.