Parallel System Research Articles

Enhancing the reliability of information in positioning systems on road transport by using parallel information redundancy

The object of research is the reliability of information in information-control systems. The work considers a solution to an important scientific and practical problem – increasing the reliability of information in real-time control systems, in particular in positioning systems on road transport. To solve this task, the use of information redundancy, in particular, parallel information redundancy, is proposed. The paper studies the influence of the probability of occurrence of a controlled event, the majority coefficient, as well as the number and quality of information sensors on the reliability of information in an information control system with parallel information redundancy. For these dependences, the corresponding plots were constructed. The paper shows that a change in the quality of information sensors by 20 % can lead to an increase in the reliability of information by more than 0.5. Also, the paper shows that an increase in the majority index by 1 can lead to a change in the reliability of information by more than 0.3. The paper investigates parallel information redundancy systems with different structures and defines formulas for calculating the probabilistic characteristics of their operation. The mathematical modeling was carried out taking into account the probability of occurrence of the controlled event, which made it possible to determine the tendencies to build information-control systems with parallel information redundancy to control events with variable probability of occurrence. The results obtained are based on the theory of probability. The results reported in this work can be used in the construction of an information and control system with a programmatically variable structure to control the occurrence of an event with a variable probability of occurrence, in particular in positioning systems on road transport

Energy and exergoeconomic analyses of parallel cross feed multi effect desalination system driven by twin-screw compressor with water injection

This work proposes the design of a parallel cross-feed multi-effect desalination system with a twin-screw compressor, incorporating water injection to enhance system performance. The improvement is achieved by injecting water during the compression process to increase the isentropic efficiency of compression. The mathematical model is solved using Engineering Equation Solver software, and the resulting mass and energy balance equations are validated against literature data. The system is analyzed and evaluated from energy, exergy, and exergy-economic perspectives, and compared with the performance of the conventional configuration in terms of specific power consumption, exergy efficiency, and cost of produced water. The impact of various operating conditions, such as the number of effects, steam temperature, compressor efficiency, and injection pressure, on specific power consumption, exergy efficiency, exergy destruction, and final product cost, is examined in this study. Additionally, factors like interest rate, plant life expectancy, and electricity cost are investigated for their effect on the final product cost. The study demonstrates that replacing the normal compressor with a twin-screw compressor result in more than a 15 % reduction in specific power consumption, approximately 4 % less exergy destruction (indicating higher exergy efficiency), and a 14 % lower unit cost of freshwater.

Environmental and energetic impact of refrigeration systems using CO2 (R744): A Cuban case study

Despite the extensive use of CO2 in food retail refrigeration units, it has never been implemented, tested or simulated in Cuba. This work aims to evaluate by simulation a Booster and Parallel compression system in twelve Cuban cities using two different semi-empirical approaches to model the compressors and the gas cooler/condenser. The compressors are modeled with a semi-empirical model and the gas cooler/condenser is modeled with a lumped model based on the ε-NTU method, discretizing the gas cooler in a one-zone model and the condenser into a three zones model. According to the results, the Booster and Parallel average consumptions are 640 MWh and 540 MWh, respectively. Both systems are less efficient than the conventional R404A refrigeration system. The lower capital costs of transcritical systems make them cost-effective solutions compared to the conventional system. Moreover, the Parallel system is an economically feasible alternative compared to the Booster one. The payback period of the Booster system is 10 to 12 years by considering the environmental and operating costs savings respect the Direct eXpansion System, while for the Parallel system the payback period is between 8 and 8.5 years. Both transcritical systems are excellent environmental alternatives to the R404A conventional system.

VTA glutamatergic projections to the nucleus accumbens suppress psychostimulant-seeking behavior

Converging evidence indicates that both dopamine and glutamate neurotransmission within the nucleus accumbens (NAc) play a role in psychostimulant self-administration and relapse in rodent models. Increased NAc dopamine release from ventral tegmental area (VTA) inputs is critical to psychostimulant self-administration and NAc glutamate release from prelimbic prefrontal cortex (PFC) inputs synapsing on medium spiny neurons (MSNs) is critical to reinstatement of psychostimulant-seeking after extinction. The regulation of the activity of MSNs by VTA dopamine inputs has been extensively studied, and recent findings have demonstrated that VTA glutamate neurons target the NAc medial shell. Here, we determined whether the mesoaccumbal glutamatergic pathway plays a role in psychostimulant conditioned place preference and self-administration in mice. We used optogenetics to induce NAc release of glutamate from VTA inputs during the acquisition, expression, and reinstatement phases of cocaine- or methamphetamine-induced conditioned place preference (CPP), and during priming-induced reinstatement of cocaine-seeking behavior. We found that NAc medial shell release of glutamate resulting from the activation of VTA glutamatergic fibers did not affect the acquisition of cocaine-induced CPP, but it blocked the expression, stress- and priming-induced reinstatement of cocaine- and methamphetamine CPP, as well as it blocked the priming-induced reinstatement of cocaine-seeking behavior after extinction. These findings indicate that in contrast to the well-recognized mesoaccumbal dopamine system that is critical to psychostimulant reward and relapse, there is a parallel mesoaccumbal glutamatergic system that suppresses reward and psychostimulant-seeking behavior.

Impact of deodorisation time and temperature on the removal of different MOAH structures: a lab-scale study on spiked coconut oil

Vegetable fats and oils are prone to contamination by mineral oil hydrocarbons due to the lipophilic and ubiquitous character of the latter. As the aromatic fraction of these hydrocarbons, MOAH, is associated with carcinogenicity, mutagenicity, and detrimental effects on foetal development, finding strategies to limit or reduce their contamination is highly relevant. Deodorisation (i.e. a refining step) has shown the ability to remove MOAH < C25 in vegetable fats and oils, but there is little information about the structures removed. Therefore, the present study investigated the impact of deodorisation conditions on the removal of different structures of MOAH in spiked coconut oil. An inscribed central composite design was built with time and temperature as variables (0.5-4h, 150-240 °C), while pressure (3 mbar) and steam flow (1 g water/g oil per hour) were kept constant. The analysis of MOAH in the oil was performed using a fully automated liquid chromatography coupled with two parallel comprehensive two-dimensional gas chromatography systems with flame ionisation and time-of-flight mass spectrometric detection. Response surfaces plotting the MOAH loss according to time and temperature were built for different MOAH fractions. The latter were defined based on the number of aromatic rings (>3 or ≤3) and the number of carbon atoms present (C16-C20, C20-C24, C24-C35, C35-C40). It was found that at 200 °C, compounds < C24, including weakly alkylated triaromatics, could be reduced to below the limit of quantification, while at 230 °C, it was possible to remove >60% of the C24-C35 fraction, including pentaromatics of low alkylation.

A parallel power system linear model reduction method based on extended Krylov subspace

With the ever-increasing scale of power systems, stability analysis and control usually bear heavy storage and massive calculation burdens. In view of this, the model order reduction technique proves valuable by constructing a low-dimensional approximate model of the original system, which is crucial for efficiently handling large-scale systems. Balanced truncation (BT), a famous model reduction method, confronts practical limitations as it requires the systems to be stable and cannot deal with unstable models. Therefore, a parallel linear balanced truncation method for power systems based on extended Krylov subspace (EKS) is proposed in this work. Besides extending the BT method to unstable systems by α-shift, the key contribution also lies in strategies to enhance the convergence of the EKS method, whereupon the algorithm improvements include effective and efficient techniques for solving dual Lyapunov equations, and parallel acceleration of the singular value decomposition. The results of the simulation case verify that the proposed method can effectively improve the convergence of the EKS method by increasing α-shift, and the improvement work in this paper reduces the total time consumption of the BT method by about 26 %–33 % of the original, exhibiting better calculation efficiency. In addition, the case studies show that the simplified model still retains the time-domain and frequency-domain response characteristics of the original high-dimensional model.

Optimization problems and maintenance policy for a parallel computing system with dependent components

Optimization problems and maintenance policy for a parallel computing system with dependent components

Hamiltonian cycles of balanced hypercube with disjoint faulty edges

The balanced hypercube BHn, a variant of the hypercube, is a novel interconnection network topology for massive parallel systems. It is showed in [Theor. Comput. Sci. 947 (2023) 113708] that for any edge subset F of BHn there exists a fault-free Hamiltonian cycle in BHn−F for n≥2 with |F|≤5n−7 if the degree of every vertex in BHn−F is at least two and there exist no f4-cycles in BHn−F. In this paper, we consider the existence of Hamiltonian cycles of BHn when F is a matching (a set of disjoint edges), and show that each edge e∉F lies on a fault-free Hamiltonian cycle of BHn−F with n≥2. The number of faulty edges in F can be up to 22n−1, which is exponential to the dimension n.

RELATIONAL DIMENSION VERSUS ARTIFICIAL INTELLIGENCE.

Thirty years ago, we proposed the similarity between the functioning of artificial intelligence and the human psyche, suggesting multiple parallels between the Freudian model proposed in the "Project for Psychology for Neurologists" and the connectionist theories applied in the generation of parallel distributed processing systems (PDP), also known as connectionist models. These models have been and continue to be the foundation of general artificial intelligences like ChatGPT, evolving and gaining prominence in everyday life. From the earliest applications in psychiatry, recreating computationally simulated modes of illnesses, to the use of deep learning models, especially in the field of computer vision for tasks such as image recognition, segmentation, and classification. Recurrent Neural Networks (RNN) and Long Short-Term Memory (LSTM) are employed for tasks involving sequences of data, such as natural language processing, or models based on the Transformer architecture, like BERT and GPT (Generative Pre-trained Transformer), which have revolutionized natural language processing. In this present work, we analyze the significance of the emergence and exponential growth of these types of tools in the field of healthcare, from medical diagnosis and patient care to psychological attention and psychotherapeutic treatment, exploring the changes and transformations in the forms of subjective expression that are arising. We also examine and argue for the importance and validity of the relational dimension proposed by our psychoanalytic approach in contrast to the potential use of these tools as treatment models.

Optimal age replacement in parallel systems with random components

Optimal age replacement in parallel systems with random components

Parenteral nutrition in the hospital setting/short-term parenteral nutrition.

This article is based on presentations and discussions held at the International Safety and Quality of Parenteral Nutrition (PN) Summit concerning the acute care setting. Some European practices presented in this article do not conform with USP general chapter <797> requirements. Nevertheless, the purpose is to cover the challenges experienced in delivering high-quality PN within hospitals in the United States and Europe, in order to share best practices and experiences more widely. Core issues regarding the PN process within an acute care setting are largely the same everywhere: There are ongoing pressures for greater efficiency, optimization, and also concurrent commitments to make PN safer for patients. Within Europe, in recent years, the use of market-authorized multi-chamber bags (MCBs) has increased greatly, mainly for safety, cost-effectiveness, and efficiency purposes. However, in the US, hospitals with low PN volumes may face particular challenges, as automated compounding equipment is often unaffordable in this setting and the variety of available MCBs is limited. This can result in the need to operate several PN systems in parallel, adding to the complexity of the PN use process. Ongoing PN quality and safety initiatives from US institutions with various PN volumes are presented. In the future, the availability of a greater selection of MCBs in the US may increase, leading to a reduction in dependence on compounded PN, as has been seen in many European countries. The examples presented may encourage improvements in the safety and quality of PN within the acute care setting worldwide.

Influence of strong directional sources in ambient seismic imaging using traffic-induced noise

Continuously moving seismic sources, such as vehicles and train cars, play a crucial role as passive sources for nondestructive exploration in urban areas. Seismic interferometry is commonly used in field data acquisition and processing using linear arrays. However, the simultaneous recording of high-energy noise, excited by buildings and factories, cannot be overlooked. We simulate moving-source seismic records with strong noises using orthogonal arrays. When strong noise originates from specific angles, the energy-phase velocity curves of arrays in different directions significantly diverge. We determine that an L-shaped array, formed by orthogonal arrays, can effectively mitigate this effect, yielding more consistent results. Nonetheless, spatial constraints often preclude the deployment of L-shaped arrays. To mitigate this issue, we develop a new parallel observation system. Field tests conducted on a main road validate that the new array is comparable with the L-shaped array in terms of dispersion extraction. Similar to synthetic data, the phase velocity extracted from the linear array field data is found to be unreliable. Drilling data align well with the inversion results of the parallel observation system. Given the challenges of urban traffic-induced signal acquisition, deploying multiazimuth arrays to minimize noise impact is essential. Considering the spatial limitations, the convenient parallel observation system emerges as a good choice.

Optimization of Endurance Performance for Quadrotor Unmanned Aerial Vehicles Driven by a Hybrid System of Solar Photovoltaic Cells and Energy Storage Batteries

The potential applications of unmanned aerial vehicles (UAVs) are vast and exciting, yet their scope could be significantly expanded if their flight endurance could be extended. The primary objective of this study is to design a hybrid power system combining solar energy and lithium batteries to enhance the endurance and energy management efficiency of unmanned aerial vehicles (UAVs). Through comparative analysis of series, parallel, and hybrid power systems, a parallel hybrid power system was chosen as the power solution for UAVs. In this paper, we detail the selection process for solar panels and lithium batteries and elucidate the design of a solar endurance enhancement system, including the application of anti-backflow and voltage stabilization modules. Additionally, we propose an energy management strategy based on finite state machines, which ensures efficient and stable operation of the system through real-time monitoring and dynamic adjustment. The methodology of this study provides an innovative and practical framework for the design and implementation of solar and energy storage battery hybrid energy management systems for UAVs.

Minimum observability of probabilistic Boolean networks

This paper studies the minimum observability of probabilistic Boolean networks (PBNs), the main objective of which is to add the fewest measurements such that an unobservable PBN becomes observable. First of all, the algebraic form of a PBN is established with the help of semi-tensor product (STP) of matrices. By combining the algebraic forms of two identical PBNs into a parallel system, a method to search the states that need to be H-distinguishable is proposed based on the robust set reachability technique. Secondly, a necessary and sufficient condition is given to find the minimum measurements such that a given set can be H-distinguishable. Moreover, by comparing the numbers of measurements for all the feasible H-distinguishable state sets, the least measurements that make the system observable are gained. Finally, an example is given to verify the validity of the obtained results.

Cross-shore parallel tidal channel systems formed by alongshore currents

Parallel tidal channel systems, characterized by commonly cross-shore orientation and regular spacing, represent a distinct class of tidal channel networks in coastal environments worldwide. Intriguingly, these cross-shore oriented channel systems can develop in environments dominated by alongshore tidal currents, for which the mechanisms remain elusive. Here, we combine remote sensing imagery analysis and morphodynamic simulations to demonstrate that the deflection of alongshore tidal currents at transitions in bed elevation determines the characteristic orientation of the parallel tidal channels. Numerical results reveal that sharp changes in bed elevation lead to nearly 90-degree intersection angles, while smoother transitions in bed profiles result in less perpendicular channel alignments. These findings shed light on the potential manipulation of tidal channel patterns in coastal wetlands, thus equipping coastal managers with a broader range of strategies for the sustainable management of these vital ecosystems in the face of climate change and sea level rise.

Formal Definitions and Performance Comparison of Consistency Models for Parallel File Systems

Formal Definitions and Performance Comparison of Consistency Models for Parallel File Systems

Working mode division and shift schedule extraction of a parallel hybrid power system

Abstract For hybrid electric vehicles, working mode division and shift schedule are two decisive factors affecting vehicle fuel economy. This paper introduces a method for vehicle working mode division and shift schedule determination on the basis of optimal system efficiency. The key index named ‘fuel-electricity conversion efficiency’ is defined and calculated. Via this method, unreasonable gear modes in specific working modes are excluded and the mode transition map and upshifting curves in each working mode are extracted. The simulation results demonstrate that, with the application of the single-motor multi-mode parallel hybrid power system, the proposed mode transition and shifting strategy can increase vehicle fuel economy by 12.99%.

Spatial ideologies on official bilingualism and co-located schools in Finland and South Tyrol, Italy

In countries with several official languages, language separation often remains a structural principle in institutional education. Co-located schools, in which two autonomously administered schools with different languages of instruction share a physical space, may challenge this separation. Such schools have existed for a long time, but increasingly insert themselves into an architectural trend that leans toward multipurpose spaces. In this paper, we utilize previous research to analyze policy discourses and educational practices that arise around bilingualism in Finland and the Italian province of South Tyrol. We introduce and analyze co-located schools through the notion of spatial ideologies, i.e. beliefs about the connection between language policies and the material organization of space. We show that in both contexts, the separation of the official languages – Finnish and Swedish in Finland and Italian and German in most of South Tyrol – is reconstructed through policy, public discourse, and material practices. The educational system maintains separate tracks for the recognized language groups. While attempts to deconstruct the parallel system are often deemed problematic, the premise of language separation is also increasingly questioned and renegotiated. Therefore, co-located schools can be viewed as contested spaces where discourses and practices promoting linguistic diversity but also parallel monolingualism circulate.

The energy management strategy of the multi-source parallel power system for the self-reconfigurable ground vehicle

The self-reconfigurable ground vehicle (SRGV) has the ability of self-assembly and self-disassembly, which is a disruptive innovation to the traditional fixed configuration ground vehicle. The basic component of the SRGV is defined as a cell unit (CU), which is a complete system capable of working independently and has the basic function of the ground vehicle. The reconfiguration of the SRGV is not only the connection of the mechanical systems but also the integration between the power sources of different CUs. To this end, this paper proposes a novel multi-source parallel power system (MSPPS) for the SRGV, whose key characteristics are multi-branch and co-bus. The MSPPS can extend any number of power sources, which greatly improves the power level of SRGV. In this paper, the MSPPS with battery power source is discussed. The disassembly and assembly of the SRGV could lead to some inconsistencies such as SoC between the battery packs of each CU. To prolong the lifetime of the battery packs and working time of the SRGV, a hierarchical proportional control (HPC) strategy and a filtered model predictive control (FMPC) strategy are proposed. Both energy management strategies can reasonably allocate the output energy between different battery packs to meet the power demand and reduce battery inconsistencies. To verify and compare the effectiveness of the proposed two strategies, numerous simulations are carried out. The simulation results show that the FMPC strategy has faster convergence speed and lower power fluctuations in the energy management process. A SRGV prototype consisting of three CUs is developed, and the experimental platform for the power system of the SRGV is successfully established. The feasibility of the proposed MSPPS architecture is validated. The proposed HPC strategy is deployed in the rapid ECU. The experiment results are similar to the simulations and effectively demonstrate the real-time performance.

A novel WDOB‐based strategy endows droop‐controlled grid‐forming converters better dynamic and static performance in DC microgrids

AbstractThe droop control strategy is popularly employed in DC microgrids. However, its virtual resistance will cause voltage deviation and reduce transient response. The DOB‐based method is proven to improve transient response in literature. However, it is analyzed in this study that this method will negatively influence the current sharing when employed in droop control. A weakened disturbance observation (WDOB) is proposed in this work to improve the drawbacks. To employ the proposed method, the equivalent models of the droop controller and the physical system are separately established, and several transformations are conducted. An auxiliary compensation is added and the current loop is considered as a whole to be transmitted into the control plant, making the traditional DOB method successfully adopted. It is obvious that the dynamic performance is improved, but it disabled virtual resistance in the steady‐state. And the current sharing cannot be achieved in a multi‐converter parallel system. The reason for this problem is analyzed from the control process and transfer function, and the WDOB solution is finally proposed. Through the proposed method, both aims of improving dynamic response and current sharing can be achieved, and the steady voltage deviation is much less than that of the traditional droop controller.