Parallel System Research Articles

Design of Combined Rainwater-Harvesting and Stormwater-Detention System with Passive Release for New Buildings in Taiwan

Taiwan experiences abundant rainfall, but faces significant water shortages, making rainwater harvesting (RWH) a potential alternative water source. Additionally, extreme rainfall events strain urban flood control systems, highlighting the need for integrated stormwater management. To address these challenges, Taiwan mandates stormwater detention (SWD) in new buildings. However, the current RWH and SWD systems are designed independently, with no combined design guidelines available. This study proposes three combined RWH and SWD systems, series, parallel, and enhanced parallel with a valve using a passive release mechanism. System performance was evaluated through short-term and long-term simulations. Short-term simulations were conducted to ensure the system’s compliance with the domestic flood control design standards. These simulations assessed the peak flow mitigation and lag times for 5-, 10-, and 25-year design storms under four scenarios. Long-term simulations used historical rainfall data to analyze the differences in the combined systems and operational plans for continuous rainfall events. Three performance indicators—volumetric reliability, the stormwater retention ratio, and the stormwater detention ratio—were employed to assess water supply and the stormwater detention performance. The short-term simulation results revealed that the system performance was sensitive to the initial conditions. The series and parallel systems performed well, while the enhanced parallel system outperformed the others under specific initial conditions and valve operations. In contrast, long-term simulations revealed that the series and parallel systems achieved higher stormwater retention and a more stable performance than the enhanced parallel system. Among the three systems, the parallel system offers reduced installation space, lower costs, and easier maintenance, making it the recommended option for Taiwan. This study provides valuable guidance for designing combined RWH and SWD systems.

Topological bound states in the continuum in a non-Hermitian photonic system

Abstract Topological insulators and bound states in the continuum represent two fascinating topics in the optical and photonic domain. The exploration of their interconnection and potential applications has emerged as a current research focus. Here, we investigated non-Hermitian photonics based on a parallel cascaded-resonator system, where both direct and indirect coupling between adjacent resonators can be independently manipulated. We observed the emergence of topological Fabry−Pérot bound states in the continuum in this non-Hermitian system, and theoretically validated its robustness. We also observed topological phase transitions and exceptional points in the same system. By elucidating the relationship between topological insulators and bound states in the continuum, this work will enable various applications that harness the advantages of bound states in the continuum, exceptional points, and topology. These applications may include optical delay and storage, highly robust optical devices, high-sensitivity sensing, and chiral mode switching.

The Future of Last-Mile Delivery: Lifecycle Environmental and Economic Impacts of Drone-Truck Parallel Systems

With rapid advancements in unmanned aerial vehicle (UAV) technology, its integration into logistics operations has emerged as a promising solution for improving efficiency and sustainability. Among the emerging solutions, a collaborative delivery model involving drones and trucks addresses last-mile delivery challenges by leveraging the complementary strengths of both modes of transport. However, evaluating the environmental and economic impacts of this transportation mode requires a systematic framework to capture its unique characteristics and minimize environmental impacts and costs. This paper investigates the Parallel Drone Scheduling Traveling Salesman Problem (PDSTSP) to evaluate the environmental and economic sustainability of a collaborative drone-truck delivery system. Specifically, a mathematical model for this delivery system is developed to optimize joint delivery operations. Environmental impacts are assessed using a comprehensive Life Cycle Assessment (LCA), including emissions and operational noise, while a Life Cycle Cost Analysis (LCCA) quantifies economic performance across five cost dimensions. Sensitivity analysis explores factors such as delivery density, traffic congestion, and wind conditions. Results show that, compared to the electric vehicle fleet, the proposed model achieves an approximate 20% reduction in carbon emissions, while delivering a 20–30% cost reduction relative to the fuel truck fleet. Drones’ efficiency in short-distance deliveries alleviates trucks’ load, cutting environmental and operational costs. This study offers practical insights and recommendations for implementing drone-truck parallel delivery systems, particularly in high-demand density areas.

Improved Direct–Parallel Active Noise Control Systems for Narrowband Noise

Narrowband active noise control (NANC) systems are extensively used to cancel narrowband noise. Direct, parallel, and direct–parallel NANC systems use nonacoustic sensors to measure rotational speeds, and a bank of signal generators then produces synchronized sinusoidal waveforms as reference signals corresponding to the fundamental frequency of the undesired noise. The performance of direct NANC systems is based on the frequency difference between two adjacent reference input sinusoids. Parallel NANC systems apply several sinewave generators and two-weight adaptive filters in parallel to attenuate these narrowband components. Conventional direct–parallel NANC systems split these sinusoids into several mutually exclusive sets such that the distance between frequencies within sets is maximized. This paper proposes an improved direct–parallel NANC system in which reference sinusoidal signals are separated by amplitude to enhance efficiency and improve noise reduction performance. Several experiments were conducted using a muffler model to verify the performance of the proposed NANC system.

Stakeholder perspectives of maternal and newborn health prioritization in South Sudan: a policy analysis

BackgroundThe maternal and neonatal mortality in South Sudan is among the highest in the world and among other fragile and conflict-affected countries. Within an evolving political economic context, this study aims to capture perspectives of current actors on drivers of the stagnating investments in maternal and newborn health (MNH).MethodsA descriptive case study guided by the health policy analysis triangle to explore contextual factors, policy content, actors’ roles and implementation processes for MNH policy and practice. A total of 20 key informants from government, humanitarian and development organizations, civil society, donors and health providers were interviewed.ResultsAccording to respondents, MNH was a priority in South Sudan due to the presence of various legal and policy frameworks. However, financial investment in MNH programs was inadequate due to the government focus on peace and stabilization, and the fragmented parallel systems run by international actors. Funding for MNH was also affected by ongoing conflicts and disease outbreaks, which diverted attention away from the issue. National initiatives to expand service coverage and funding are either inadequate or not well studied. In addition, gendered attitudes and norms continue to impede care seeking, service provision and inclusivity in decision-making for improving MNH prioritization. Stakeholders highlighted the need for accountability to sustain progress and close policy implementation gaps.ConclusionThis study highlighted relevant challenges and opportunities for improving MNH outcomes in South Sudan and similar fragile contexts. Government ownership of the MNH agenda is needed, so is strengthening of national initiatives, gender equity, actor coordination and accountability mechanisms.

Strategic Maintenance Approaches for Enhanced Reliability in Parallel System

Strategic Maintenance Approaches for Enhanced Reliability in Parallel System

PARALLEL PERFORMANCE OF THE EXPLICIT FDTD METHODS APPLIED ON 3D ACOUSTIC WAVE EQUATION

The 3D acoustic wave equation is a second-order linear hyperbolic partial differential equation. It is widely studied in acoustics, fluid dynamics, electromagnetism, and seismology within both science and engineering fields. Among the various numerical methods, the finite difference method is considered to be the simpler to understand and easy to implement. Based on the discretize schemes finite difference time domain method described by the explicit scheme in which spatial second order derivatives are evaluated at the previous time step. The solution of 3D acoustic wave equation may be required on the high-resolution mesh points consequently more computational resources are required. In this study parallel algorithm for the numerical solution of 3D acoustic wave equation is proposed and designed by using data parallel approach and message passing schemes. The algorithm is implemented on shared memory parallel system using MATLAB parallel computing mode. The parallel performance of the designed algorithm is analyzed on different mesh sizes and time steps. It is revealed that the proposed algorithm may reduce computational time up to 3 times as compared to sequential solution algorithm. The proposed parallel algorithm remains more efficient on workers while for the efficiency of the algorithm drops because of the high communication time. The results of the proposed research could be utilized in the large-scale simulations of 3D acoustic wave equations and may enable to simulate the acoustic wave pressure at more refined meshes on high performance computing systems.

Performance analysis of different flow rates and dust accumulation in rectangular micro heat pipe Photovoltaic/Thermal parallel system

Performance analysis of different flow rates and dust accumulation in rectangular micro heat pipe Photovoltaic/Thermal parallel system

Performance Optimization in Three-Modality Biometric Verification using Heterogeneous CPU-GPU Computation

This paper proposes a method to improve the performance of tri-modal biometric verification using a heterogeneous computing system exploiting the synergy between CPU and GPU. The main objective is to reduce the time required for verification while maintaining the system's accuracy. The design of this system is based on a decision fusion algorithm based on the logical OR connector, enabling the results of the three modalities to be combined. The implementation is being carried out in C# with Visual Studio 2019, using the Task Parallel Library to parallelize tasks on the CPU, and OpenCL.NET to manage processing on the GPU. The tests carried out on a representative sample of 1,000 individuals, show a clear improvement in performance compared with a sequential system. Execution times were significantly reduced, ranging from 0.03 ms to 0.67 ms for data sizes between 50 and 1000. Analysis of the performance gains, based on Amdahl's law, reveals that the proportion of tasks that can be parallelized remains higher in heterogeneous systems than in parallel and sequential systems, even though part of processing remains sequential for large data sizes. This study highlights the ability of heterogeneous computing systems to effectively reduce the verification time of biometric systems while maintaining an optimal balance between processing speed and overall efficiency. The results demonstrate the potential of this approach for advanced biometric applications, particularly in distributed environments.

Performance analysis on an integrated three-area thermal AGC system with various wind velocities considering HCSA-optimized PI-TIDN Controller

This article investigates the impact of a high-voltage direct-current (HVDC) link and a wind turbine system (WTS) on the dynamics of a three-area thermal automatic generation control (AGC) system. A novel controller, the cascade of proportional-integral (PI) and tiltintegralderivative (TID) with filter coefficient (N) (PI-TIDN) controller is projected. The WTS units are subjected to various wind velocity scenarios, including fixed and random wind velocities. The controller parameters are concurrently enhanced using the hybrid crowsearch algorithm (HCSA). The system dynamics corresponding to the PI-TIDN controller are superior to those of PIDN and TIDN controllers. Additionally, studies with different wind velocities demonstrate that responses with fixed wind velocities are better than those with random wind velocities. Moreover, integrating WTS units with the thermal system improves dynamics compared to the thermal system alone. It is also apparent that the parallel AC-HVDC system enhances dynamics. Furthermore, sensitivity analysis exposes that the PI-TIDN controller values at nominal settings are vigorous and do not require retuning.

Using Air Plasma‐generated High‐Valence NOx for Olive Oil Activation to Produce High‐Performance Antimicrobial Agents

ABSTRACTThis study develops a time‐ and performance‐efficient process for oil activation with enhanced bioreactivity. Instead of ozone foaming, plasma‐activated gas (PAG) bubbling has been, for the first time, employed for potent olive oil activation. A parallel system integrating dielectric barrier discharge (DBD) and gliding arc discharge (GAD) devices generates air‐PAG rich in high‐valence nitrogen oxides (NOx) and O3. By adjusting DBD and GAD power ratios, PAG composition is controlled. At a power ratio of 1:1, NOx content and the sterilization performance of thus‐obtained plasma‐activated oil (PAO) reach their peaks. Compared to traditional ozonated oil and plasma‐activated water (PAW), PAO demonstrates superior bacterial‐killing ability and extended storage stability, showing outstanding capacity in medical and food applications as a green agent.

Leaving No One Behind: Party Clientelism in Social Welfare in Serbia

This article analyzes the functioning of party patronage and clientelism in the centers for social work. Building on previous research, based on qualitative research conducted in 2023 in Serbia, we examine parasitic relations of informal and formal institutions and their ability to nihilate the legal system and create a parallel or dual normative system. The initial step in institutional capture is party patronage and the deprofessionalization of public services. We further demonstrate how party cadre employed in public institutions create and reproduce clientelist networks and divert the working of the institutions. Finally, most public sector employees quietly comply with the expectations to work in the network’s interest, creating a new culture of fear and professional and civic passivity. We argue that informal institutions of clientelism parasitize formal institutions and that capturing institutions and society transforms the internal norms of clientelist networks into social norms, creating a backbone of normative dualism.

Adaptive Control Strategy of Parallel Virtual Synchronizer of Wind–Solar–Storage Microgrid Based on Neural Network

In order to solve the problem that the impedance of each line of the parallel system of the wind–solar–storage virtual synchronous machine(VSG) is inconsistent, resulting in the power circulation between the parallel VSG, a multi-parameter collaborative adaptive control strategy for the parallel virtual synchronizers of a wind–solar–storage microgrid based on a neural network was proposed. Firstly, the topology of the virtual synchronous machine parallel system of the wind–solar–storage microgrid was built, and the VSG was analyzed. Then, the neural network algorithm was used to realize the adaptive adjustment of each parameter of VSG, which improves the uneven power distribution and the influence of circulation. Next, the parameters of multiple parallel VSG control systems were configured. Finally, MATLAB2021a/Simulink was used to model the system, and the VSG capacity under different scale conditions was simulated and analyzed. The simulation results show that when the capacity ratio of VSG1 and VSG2 is 1:1, the active power output is 9000 W, and the reactive power output is 7500 Var, which realizes accurate distribution, and when the capacity ratio of VSG1 and VSG2 is 2:1, the output values of active power and reactive power are 12,000 W/6000 W and 10,000 Var/5000 Var, and the output is carried out according to the ratio of 2:1, which shows that the control strategy can effectively improve the power allocation accuracy, suppressing circulation.

Reliability Estimation of Parallel Systems with Diverse Failure Modes: Semi-Markov Model Approach

This paper introduces a novel system consisting of two dissimilar units operating in parallel, each with distinct failure modes. This flexibility in units characteristics minimizes the risk of simultaneous failures due to common causes. The system’s mathematical model is developed using a semi-Markov approach, and a numerical method based on the regenerative point technique is applied to estimate various reliability measures, such as the mean time to system failure (MTSF) and system availability. Failure rates are modeled as exponentially distributed, while repair rates are allowed to follow arbitrary distributions. Additionally, the proposed model undergoes graphical analysis to evaluate system performance under varying parameters.

Chaos secure communication based on free-running VCSEL system

Abstract In this paper, we propose a parallel injection chaotic system involving three free-running 
vertical-cavity surface-emitting lasers (VCSELs). First, the chaotic synchronization 
performance of the system is evaluated using the cross-correlation function. Then, we analyze 
in detail the effects of injection strength, frequency detuning, and parameter mismatch on the 
chaotic synchronization and information transmission of the system. Numerical studies 
indicate that the proposed parallel injection chaotic system based on three VCSELs can 
achieve high-quality chaotic synchronization over a wide bandwidth and a broad range of 
input parameters. Furthermore, even in the case of parameter mismatch, high-quality chaotic 
synchronization and communication can still be achieved. Additionally, with appropriate 
injection strength, the system can compensate for the efficiency reduction caused by 
parameter mismatch.

The transformative relation between publishers and editors: Research quality and academic autonomy at stake

Abstract The prevalence of scientific journals amid the expansion of digital platforms and mega-infrastructures features the persistent will of scholars to give part of their time to this endeavor, which is frequently a thankless task and subject to intense pressures. In this paper, we focus on scholarly editorship and the existing commercial interferences to explore whether this has an equal incidence in publishing circuits outside the mainstream. For this purpose, we describe the case of Latin America, where a parallel value system is observed through indexation criteria focused on academic quality and independent editorship. We examined 1,971 Scielo and Redalyc journals stressing the features of editorial teams, publishing institutions, and calibrating the penetration of the APC business model. We argue that the development of this regional publishing circuit, along with the value system that explains its survival, finds its main strength in its public nature and the crucial role of universities’ autonomy, although its main weakness in the absence of an interoperable infrastructure capable of broadening its circulation. Eventually, we discuss the idea of predatory publishing and its evolution from the representation of journal backwardness to fraudulent for-profit publications, proposing to reorient the value of scientific journals onto their academic autonomy. Peer Review https://www.webofscience.com/api/gateway/wos/peer-review/10.1162/qss_a_00343

Research on Circulating Current Suppression Control of Parallel Inverters

Circulating current suppression can effectively improve the reliability and redundancy of parallel inverter systems. The mechanism and influencing factors of the low- and high-frequency zero-sequence circulating current (ZSCC) are analyzed in this study. Based on a mechanism analysis and the built mathematical model, the composite control strategy of zero-sequence voltage difference (ZSVD) compensation and virtual inductance is proposed to suppress the low- and high-frequency ZSCC. In the composite control strategy, the low-frequency ZCSS (LF-ZCSS) is suppressed by the ZSVD compensation method, and the HF-ZCSS is suppressed by the virtual inductance method. The ZSVD compensation is incorporated into the SVPWM as an input to regulate the modulation and suppress the LF-ZCSS, and virtual inductance is introduced into the current control loop to suppress the HF-ZCSS. A parallel system prototype composed of two 6 kW inverters is constructed. The experiments show that the ZSCC of the parallel system is reduced by 45%, which verifies the effectiveness of the proposed composite control strategy.

Cooperative Control Strategy for Power Quality Based on Heterogeneous Inverter Parallel System

Multi-functional grid-connected inverters (MFGCIs) have attracted much attention for their auxiliary services to improve power quality in microgrids and new energy generation systems. However, power quality enhancement based on MFGCIs often only considers a single control method. The regulation potential of multiple control-type inverters is not fully utilized. To suppress harmonic and support voltage, a cooperative control strategy based on the parallel system of a grid-following (GFL) inverter and a grid-forming (GFM) inverter is proposed. The topology of the MFGCIs is introduced and a mathematics model is deduced. Secondly, a specific-order harmonic compensation method is proposed for the harmonic suppression at the point of common coupling (PCC). The harmonic current is realized to be shared according to the inverter capacity. The reactive power output of the heterogeneous inverters is coordinated by calculating the reactive power compensation and reactive power allocation so that the PCC voltage always stays near the rated voltage. Finally, the effectiveness of the proposed control strategy is verified by simulation and experiment.

THE ROLE OF TEACHERS IN THE PROMOTION AND PRESERVATION OF GORANI CULTURAL IDENTITY IN KOSOVO AND METOHIJA

This paper examines the impact of teaching staff on promoting and preserving Gorani identity in Gorani schools in Kosovo within the Serbian educational system. The researchers employ a mixed-methods approach, combining surveys and semi-structured interviews. Seventh and eighth-grade students from five primary schools and third and fourth-year high school students were surveyed. Interviews were conducted with the principals of each school and one teacher per school, except for one school where communication could not be established. The structured survey includes 16 questions (one open-ended), based on a 5-point scale, aiming to assess the effectiveness of teachers in promoting Gorani culture, students’ knowledge of the culture, students’ participation in cultural activities, and students’ interest in preserving Gorani heritage. Our findings indicate that schools play a significant role in cultural preservation and promotion. However, the full potential of the school system in this regard has yet to be realized, as cultural knowledge transfer largely depends on the enthusiasm and self-initiative of the teaching staff. The main challenges are not solely curricular, as teachers often use certain lessons to promote Gorani culture but are also influenced by Kosovo’s complex political and social landscape. While financial support from Belgrade is available, there is a lack of initiative from both authorities and schools. This study also suggests two key areas for future research: first, a comparative study including Albanian- and Bosnian-language schools could enhance understanding of parallel educational systems in post-conflict settings. Second, an exploration of the Gorani community’s position within the broader political landscape of the Belgrade-Pristina dialogue and the Brussels process could provide further insight.

Two redundancy mechanisms in series and parallel systems with heterogeneous dependent components

Two redundancy mechanisms in series and parallel systems with heterogeneous dependent components