Recovery Scheme Research Articles

Market participation and pastoral welfare in drought-prone areas: A dose-response analysis

The low market participation of pastoral livestock producers is a challenge to the development of a climate-resilient economy in drought-prone areas. Without deliberate and well-designed efforts to transform livestock production into a thriving profit-oriented commercial business, the development of pastoral societies will remain far-fetched. By applying bivariate selection model and dose-response function to a case study of 357 pastoral households in Ethiopia, this study examines pastoralists’ participation in goat markets and the impact of participation on per capita income, poverty headcount, and poverty gap. Our results show that the propensity and intensity of participation of pastoralists in goat marketing were influenced by flock size, transaction costs (TC), and access to veterinary services. An important finding in this study is that pastoralists are willing to pay for marketing services up to 97 % of the total variable TC, indicating the financial feasibility of public investment in the development of market infrastructure through cost recovery schemes. The results also reveal that participation in goat marketing has a positive impact on per capita income, poverty headcount, and poverty gap. These findings shed some light on more practical strategies for poverty reduction among pastoralists.

Investigation of sodium bicarbonate media blasting technology for achieving the cleaner production of graphite deposition reactor cleaning process: Process optimization and simulation

The periodic cleaning of silicon nitride residues on the graphite deposition reactor surface is a critical process for producing silicon wafers in the photovoltaic manufacturing industry. A green, non-erosive and sustainable sodium bicarbonate media blasting technology (SBMBT) was investigated in this research, aiming for providing an alternative to the widely-used polluting liquid hydrofluoric acid soaking method in the industry. By comparing the cleaning behavior of different blasting media (sodium bicarbonate, alumina, glass bead and walnut shell) under various blasting angles and pressures, the most appropriate cleaning process parameters (30° and 0.3 MPa) and efficient removal rate (0.085 cm2/s) of SBMBT were determined based on the statistical characterization of surface roughness data. Under the most appropriate cleaning process parameters, the mean value of roughness (Ra = 2.119 μm) and cleanliness of graphite deposition reactor surface that was cleaned by SBMBT could meet industry standards. Based on the stress sample data provided by the six identical simulations on each of the nine parameter combinations, the multiple-impact cleaning mechanism of SBMBT was revealed using the LSTC dynamics (LS-DYNA) particle impact model and a high-speed camera. Based on five sets of the recovery experiments data, the mean value of blasting media recovery rate obtained in the validation of the designed sodium bicarbonate media recovery scheme was 79.98%, and the consistency of the media crystal form before and after recovery was confirmed by PXRD. As the experimental results indicate, SBMBT is a green technology with low damage, no residue, and can effectively alleviate the problem of solid waste treatment, which is worthy of being applied in graphite deposition reactor cleaning processes.

FFRLI: Fast fault recovery scheme based on link importance for data plane in SDN

For many years, link fault recovery has always been a hotspot problem in Software-Defined Networking (SDN). Current researches mainly include proactive and reactive schemes. However, proactive scheme wastes the Ternary Content Addressable Memory (TCAM) and bandwidth resources seriously, and reactive scheme has a long recovery time. Hence, none of them qualifies as a complete solution. In this paper, we present a new two-stage fast fault recovery scheme based on link importance (FFRLI) to balance backup resource consumption and recovery time. In stage 1, FFRLI innovatively introduces Markov chains and pinning control to evaluate the importance and rank of different links, and labels them as main link, minor link and edge link. On this basis, in stage 2, we develop different recovery schemes and optimization objectives for different links. More specifically, for main links, we minimize the hops of backup path and install flow rules into switches in advance. Similarly, we store backup path of minor link in controller, and improve A-star algorithm to minimize hops and distance of backup path. Finally, FFRLI takes reactive recovery for edges link and adopts bidirectional Dijkstra to reduce backup path calculation time. Compared to existing state-of-the-art solutions, the simulation results present that FFRLI can effectively balance the consumption of backup resource and fault recovery time, and achieve fast fault link recovery.

Countering Local Disaster Capitalism

Disaster capitalism creates political and economic space for neoliberal projects to benefit the wealthy disproportionately while marginalizing Indigenous groups. This paper examines how and the extent to which local disaster capitalism has affected Indigenous communities in Nepal’s Kathmandu Valley, as they recover from the 2015 earthquakes, and how local disaster capitalism ought to be countered. Based on an in-depth analysis of local disaster capitalism in Rudrayani Guthi, Nepal, the findings of this study demonstrate that Indigenous peoples have been negatively affected by state-sponsored disaster recovery schemes, whereas wealthy people and businesses have benefitted from them. Such schemes focus on “physical reconstruction” and “economic development”, dispossessing Indigenous lands to pave the way for housing, motorways, greenfield urban development, and hydropower. Many Indigenous groups are forced to be part of such schemes, while local disaster capitalism continues in the name of “disaster recovery”. The paper highlights the unfortunate reality of the local disaster capitalism taking shape and destroying Indigenous lives and livelihoods. The paper concludes by offering some principles used by Indigenous peoples while countering local disaster capitalism through confrontations with powerful actors and while protecting their land during the process of disaster recovery.

Flight Conflict Resolution and Trajectory Recovery Through Mixed Integer Nonlinear Programming Based on Speed and Heading Angle Change

A scheme for conflict resolution with trajectory recovery is proposed to solve the problem of multi-aircraft flight conflict. First, the conflict resolution problem is modeled as an optimal control problem. The weighted sum of the speed change and the heading angle change is defined as the objective function. The limitations of distance, aircraft performance, and route width are taken as constraints. Second, the optimization problem is resolved by mixed integer nonlinear programming. Conflict resolution with trajectory recovery is then achieved by speed and heading angle changing three times based on the optimal solution; whether the speed and heading angle need to be changed depends on the corresponding weight coefficients in the objective function. Finally, the applicability and superiority of the designed conflict resolution scheme are verified, which is of great significance to the application of conflict resolution with trajectory recovery schemes in automated air traffic control systems.

Post-Disaster Resilience Optimization for Road–Bridge Transportation Systems Considering Economic Loss

After a disaster, the recovery sequence of damaged bridges in a road–bridge transportation system greatly influences system restoration time and total economic loss. In this paper, the skew of recovery trajectory is introduced to evaluate the average restoration time, and the total economic loss is extended to consider the indirect loss, such as the energy consumption of detours or the emergency service fee. So, the post-disaster resilience optimization model is constructed by minimizing the total economic loss. The improved genetic algorithm is developed to obtain the optimal recovery scheme for damaged bridges by considering the recovery sequence and repair modes. The composition and influence factors of total economic loss are analyzed through three experiments. The experimental results show that the indirect loss accounts for approximately half of the economic loss, while the higher price of emergency service promotes the reduction of indirect loss using the expedited modes to repair damaged bridges. Moreover, to minimize the total economic loss, it is essential to design the optimal recovery scheme (repair sequence and repair mode) wisely to balance the conflicts between indirect loss and direct loss.

Unscented Kalman Filter with Joint Decision Scheme for Phase Estimation in Probabilistically Shaped QAM Systems

A carrier phase estimation method based on the unscented Kalman filter (UKF) is proposed for probabilistically shaped (PS) quadrature amplitude modulation (QAM) systems. We further integrate a joint decision scheme into the proposed UKF−based algorithm to prevent the correlated erroneous decisions in the phase recovery scheme caused by the impact of PS. The proposed method achieves the performance benefit for PS constellations in optical transmissions by partitioning the constellation symbols suitably and utilizing both the maximum a posterior probability (MAP) and maximum likelihood (ML) detection. The results of numerical simulation and experimental verification reveal that the proposed method performs better than the conventional CPR algorithms in PS systems.

On a self-recovery digital watermarking scheme robust against spatial and temporal attacks on compressed video

In recent decades, the use of digital media has increased. With it, digital media exposure to unwanted manipulations that, although unintentional, can affect third parties. These manipulations in digital watermarking are known as attacks, consisting of intentional or unintentional editing of multimedia content such as images, videos, or audio streams. For video sequences, attacks can be performed in spatial and temporal domains. The former includes changes to individual frames, while the latter involves altering sub-sequences, such as inserting or deleting frames.This work aims to achieve approximate recovery from these attacks using digital watermarking. Unlike most existing works, this scheme uses the compression domain since most video applications use some compression standard to transmit and store these sequences. By adapting popular image block-based popular recovery schemes for large video sequences and using a novel scrambled watermark mapping, satisfactory recovery and visual quality results are achieved.

Fiber-optic temperature sensor based on glass Fabry – Perot interferometer

In this work, analytical expressions are obtained that allow one to determine the shift of the central wavelength of a four-component addressable fiber Bragg structure (FAFBS). The computer simulation of the use of CHAVBS in the problems of measuring the temperature of the windings of power transformers has been carried out. Simulation showed that more accurate temperature measurement results are obtained when the circuit operates in reflection, i.e. at an additional address frequency. With the use of FAFBS, there is no need to install additional frequency filters. It is not required to use address component recovery schemes compared to the three-component AFBS option. This fact is a significant difference between the developed systems based on AFBS and systems based on two- and three-component AFBS.

Partial Recovery of Coherence Loss in Coherence-Assisted Transformation.

Coherence-assisted transformation under incoherent operations is discussed. For transformation from the pure state to the mixed state, we show that the coherence loss can be partially recovered by adding auxiliary coherent states. First, we discuss the coherence-assisted transformation for qubit states and give the sufficient and necessary condition for the partial recovery of coherence loss, and the maximum of the recovery of coherence loss is also studied in this case. Second, the maximally coherent state can be obtained in the above recovery scheme, so we give the full characterization of obtaining the maximally coherent state in a qubit system. Finally, we show that the coherence-assisted transformation for arbitrary finite-dimensional main coherent states and low-dimensional auxiliary coherent states is always possible, and the coherence loss also can be partially recovered in these cases.

Joint timing recovery and adaptive equalization based on training sequences for PM-16QAM faster-than-Nyquist WDM systems.

Since the timing error detectors sensitivity (TEDS) of the timing recovery algorithm is close to zero under the singularity condition of azimuth θ about ±π/4 and differential group delay (DGD) about n × 1/2T (n is an odd number, T is the symbol period), it makes the squared Gardner phase detector (SGPD) timing recovery algorithm fail to achieve timing synchronization. What's worse, in the faster-than-Nyquist wavelength division multiplexing (FTN-WDM) systems, the tight filtering introduces inter-symbol-interference (ISI) so severe that the convergence cost of the SGPD timing recovery algorithm is extremely large even under the non-singularity condition. This paper proposes a joint timing recovery and adaptive equalization scheme for FTN coherent systems based on training sequences that could calculate channel matrix and indicate polarization characteristics, thereby avoiding the influence of azimuth on adaptive equalization and polarization demultiplexing (AEPD) embedded in the timing recovery feedback loop. Since embedded AEPD could compensate for most of DGD, the TEDS could be restored and timing synchronization could be achieved under the above adverse conditions. Thanks to the innovative scheme, which equalizes ISI and DGD during the feedback process of the loop, the convergence cost of timing recovery could be reduced with similar computational complexity compared with the conventional one. The simulation results of 128 GBaud polarization multiplexing (PM) 16-quadrature amplitude modulation (QAM) FTN-WDM transmission systems demonstrate that the proposed scheme could stably achieve timing synchronization under the singularity condition. And compared with the conventional scheme, the convergence cost is reduced by at least 42% @ 0.9 acceleration factor. In addition, 40 GBaud PM-16QAM FTN experiment results show that the proposed scheme could not only achieve timing synchronization stably but also exhibit an optical signal-to-noise ratio tolerance gain of 0.8 dB compared with the conventional scheme under 800 km transmission.

An efficient and secure identity-based integrity auditing scheme for sensitive data with anti-replacement attack on multi-cloud storage

The rapid growth of cloud storage brings forth significant difficulties in ensuring the integrity of data owners' sensitive data. Multi-cloud storage systems, which motive to enhance trustworthiness, are vulnerable to rigorous replacement attacks. These insidious attacks involve malicious actors substituting legitimate data with counterfeit versions, leading to compromised integrity and fraudulent audit outcomes. We propose a novel identity-based data integrity auditing protocol tailored for multi-cloud storage environments to tackle this challenge. Our protocol leverages a Third-Party Auditor (TPA) to delegate data authenticity and auditing responsibilities, employing identity-based blind signatures with a robust data recovery scheme. By eliminating the need for cumbersome public key certificate management, our solution effectively protects data owners' sensitive data while ensuring confidentiality across multiple cloud providers, thereby mitigating the risk of replacement attacks. A thorough security examination shows the proposed system resists forging, replacement attacks, and data confidentiality violations. A rigorous performance experiment also reveals outstanding computational and communication efficiency that outperforms current methods in tag production, proof generation, and verification. Our protocol offers an extraordinary balance of security and efficiency, making it particularly useful for auditing patent-sensitive data in multi-cloud storage. Our proposal provides a timely and effective way to protect sensitive data and prevent attackers in multi-cloud storage settings at a time when replacement attacks pose a serious concern.

Research on Speed Control Methods and Energy-Saving for High-Voltage Transmission Line Inspection Robots along Cable Downhill

To ensure the safe operation of high-voltage transmission line inspection robots during downhill descents without power and extend their range after a single charge, this paper proposes an energy-saving speed control method for the inspection robot’s walking wheel motor on downhill slopes by integrating feedback braking and fuzzy PID control. By combining the parameter equation of the overhead catenary line and the structural characteristics of the overhead transmission line, this paper analyzes the relationship between the driving torque of the inspection robot’s wheels and the horizontal displacement along the transmission ground wire before and after descending. Based on this analysis, a speed control and energy recovery scheme is developed for the inspection robot, which combines front-wheel feedback braking with rear-wheel regenerative braking. The fuzzy PID method is utilized to adjust the PWM duty cycle to achieve energy-efficient speed control of the inspection robot’s rear walking wheels. Additionally, to improve the energy density and specific power of the robot’s energy storage unit, a composite power source consisting of lithium batteries and supercapacitors is employed to recover energy from the front walking wheels through feedback braking. The combined simulation results indicate that, compared to fuzzy control and PID control, fuzzy PID control better regulates the robot’s speed under varying slopes, wind resistance, and cable roughness. A downhill speed control system for the inspection of the robot’s walking wheel motor was designed, and its effectiveness was validated through simulated high-voltage line experiments. The fuzzy PID control was demonstrated to effectively maintain the rear walking wheel speed within the targeted range during downhill descents. When descending along a fixed 30° angle cable, the fuzzy PID control resulted in an increase of 5.28% and 14.26% in the state of charge (SOC) of the supercapacitor compared to PID control and fuzzy control, respectively. Moreover, when descending along fixed angle cables of 10°, 20°, and 30°, as well as a variable angle cable ranging from 30° to 0°, the SOC of the supercapacitor increased by 17.55%, 26.25%, 38.45%, and 31.29%, respectively. This demonstrates the effective absorption of regenerative braking energy during the robot’s downhill movement.

Numerical Study of a Three-Bed Adsorption Chiller Employing an Advanced Mass Recovery Process

The performance improvement of a three-bed (equal bed) adsorption chiller employing an advanced mass recovery process has been numerically studied in this paper. The mass recovery scheme is used to improve the cooling effect and a CFC-free-based sorption chiller driven by the low-grade waste heat or any renewable energy source can be developed for the next generation of refrigeration. Silica gel/water is taken as adsorbent/adsorbate pair for the present chiller. The three-bed adsorption chiller comprises with three adsorber/desorber heat exchanger, one evaporator and one condenser. In the present numerical solution, the heat source temperature variation is taken from 500C to 900C along with coolant inlet temperature at 300C and the chilled water inlet temperature at 140C. In the new strategy, if any one bed (3rd bed) is connect with the evaporator during pre-heating or pre-cooling time then it will give better performance than that of existing system. In this strategy, mass recovery process also occurs in all bed. A cycle simulation computer program is constructed to analyze the influence of operating conditions (hot and cooling water temperature) on COP (coefficient of performance), and CC (cooling capacity).

Project Investment Analysis on New Oil and Gas Field Development (M-X) at Pt. PTM

PT.PTM as one of major oil and gas company in Indonesia contributes highly to fulfilling oil and gas demand in Indonesia. However, with more than 40 years of operation, PT. PTM is currently at its declining phase. Aggressive development projects have been planned to sustain PT. PTM production. The latest development project is M-X new field developments. This Final Project is intended to assess the M-X Project feasibility in terms of economic terms considering possible dynamic changes in several factors. The results of this final project will help PT.PTM management decide whether to invest in the development of the M-X field. Both Discounted and Non-Discounted Cash Flow (DCF and Non DCF) will be used in the M-X Project investment analysis. Revenue and cost breakdown will follow Production Sharing Contract (PSC) – Cost Recovery scheme as applied for PT. PTM. The Non-DCF analysis shows that 264.65 MMUSD net cash flow will be generated for the Government due to M-X development while PT. PTM will gain 49.97 MMUSD with payback period of 3 years after M-X production. DCF analysis result shows that Project Net Present Value (NPV) is 4.35 MMUSD with an IRR of 12%. Financial risk due to dynamic changes in oil and gas project is analyzed using Montecarlo simulation that resulted on 23.3% probability to have negative NPV with Mean NPV of 13.93 MMUSD. The analysis result from Non-DCF and DCF method shows positive result for PT. PTM management to proceed with investment planning for M-X field development.

Experimental evaluation of the impact of induced fractures on cyclic solvent injection performance in low-permeability hydrocarbon reservoirs

Recovery factors associated with primary recovery (pressure depletion) schemes are often small (<5–10%) for low-permeability hydrocarbon reservoirs. As a result, cyclic solvent injection (CSI) schemes, using CO2 and produced gas, are currently being considered for enhanced hydrocarbon recovery (EOR). Fracture networks, generated during hydraulic fracturing stimulation, affect both primary and enhanced recovery by increasing the surface area contacted with the low-permeability reservoir matrix. However, experimental studies of the impact of induced (hydraulic) fractures on CSI performance are sparse, particularly those that provide a realistic representation of the fracturing process by inducing fractures under stress to better represent fracture conditions (e.g., fracture surface area, fracture surface roughness). Therefore, the primary objective of this work is to develop a laboratory-based workflow for evaluating the effectiveness of fracture system in tight oil reservoirs to enhance the oil recovery during a typical CSI cycle using a combination of core-scale techniques.An in-house core-flooding methodology, that combines ‘in situ’ fracturing and cyclic gas injection, was applied. The experimental procedure includes: 1) performing multiple cycles of lean gas (i.e., 80% C1 + 20% C2) injection into an oil-saturated ‘intact’ core plug until maximum oil recovery (5%) is reached, 2) artificially fracturing the core plug under stress, 3) repeating multiple cycles of lean gas injection into the artificially-fractured core plug, under similar experimental conditions as those used for the intact core, until maximum oil recovery (23%) is reached, and 4) measuring the fractured-core liquid permeability. A well-characterized tight siltstone core plug sample obtained from the Canadian Montney Formation was analyzed as an example. The experimental results indicate that 1) fracturing under stress results in an increase in surface area and permeability, and 2) the recovery factor is enhanced by ∼ 18% after fracturing (e.g., from ∼ 5% for intact core plug to ∼ 23% for artificially-fractured core plug).This study provides a proof-of-concept experimental approach for evaluating the impact of induced fractures on CSI recovery using an identical core plug sample (intact and fractured). The proposed experimental methodology could serve as a workflow for laboratory-scale evaluation of the impact of induced fractures on CSI performance in tight hydrocarbon reservoirs.

Impact of recovery cycles on the cascade hybrid adsorption-vapor compression chillers

This study analyzed a cascade-type hybrid adsorption-vapor compression chiller. This chiller is a combination of an adsorption chiller and a vapor compression chiller, where the amount of energy absorbed in the evaporator of the adsorption chiller is equal to the heat rejected in the condenser of the vapor compression chiller. The study examined three distinct recovery schemes: heat recovery, mass recovery, and a combined heat-mass recovery approach, applied to the hybrid chiller to assess their effect on the chiller's performance and potential energy savings. The study used MATLAB and CoolProp for mathematical modeling, and the model closely aligned with earlier research. The study found that implementing mass recovery significantly improved energy efficiency and coefficient of performance compared to the basic cascade hybrid system. However, heat recovery had a negative impact on the hybrid chiller. Additionally, the study proposed an optimal duration for mass recovery in the hybrid cascade system. This research offers valuable insights into the advantages of using hybrid chiller systems and emphasizes the significance of incorporating heat and mass recovery in their design and functioning.

A watermarking-based authentication and recovery scheme for encrypted audio

A watermarking-based authentication and recovery scheme for encrypted audio

Studies on hydrometallurgical recovery of rare earth elements as mixed fluoride compound from coal fly ash using environmentally friendly organic acid

ABSTRACT Coal fly ash (CFA) emerged as one of the potential secondary source of rare earth elements (REEs). This paper discusses development of a process scheme for the recovery of REE from a CFA sample, assaying total REE of about 0.2% using environmentally benign lactic acid (LA) as leachant. The CFA is generated at a lignite coal-based thermal power plant. The REE occurs dominantly in an ion-exchangeable form and also as bound to iron oxides. Nearly 25% of total REE is constituted of heavy rare earth elements (HREEs). About 89% of REE values were found leachable with LA at 80°C in 2 h of reaction time at 10% solids content. Kinetic analysis of leaching process shows that the reaction between CFA and LA is chemical reaction controlled with activation energy of 42–45 kJ/mol. The dissolved REE values were extracted quantitatively from leachate using D2EHPA solvent diluted in kerosene and stripped back with 6 N HCl. The REE in strip liquor was precipitated as mixed REE-fluoride concentrate of purity 86% with precipitation efficiency of 98%. A scheme for quantitative recovery of LA from barren stream was developed for its recycle in leaching circuit.

Speech watermarking based tamper detection and recovery scheme with high tolerable tamper rate

Speech watermarking based tamper detection and recovery scheme with high tolerable tamper rate