bluuebunny/crossref_metadata_2025 huggingface dataset:
RF-KELM indoor positioning algorithm based on WiFi RSS fingerprint
Authors: Hou Bingnan , Wang Yanchun
Published: December 2023

WiFi-based fingerprint indoor positioning technology has been widely concerned, but it has been facing the challenge of lack of robustness to signal changes, and the positioning service requires fast and accurate positioning estimation. Therefore, an random forest-kernel extreme learning machine (RF-KELM) positioning algorithm with good comprehensive performance is proposed in this paper. Both offline and online phases are included by this algorithm. In the offline phase, the original data of WiFi fingerprint is first transformed into a form more suitable for positioning. Then, access point (AP) selection is performed on the fingerprint database containing many useless APs, in which an RF which can evaluate the importance of features is used. Finally, the KELM is trained with the sub-database that have undergone data transformation and AP selection. In the online phase, firstly, the obtained signal is processed, and then the trained KELM is used to predict the position of the data processed signal. In this paper, the performance of the proposed RF-KELM positioning algorithm is thoroughly tested on a publicly available dataset, and the experimental results demonstrate that the proposed algorithm not only has high positioning accuracy and robustness, but also takes only 0.08 s to position online.
Density of periodic measures and large deviation principle for generalised mod one transformations
Authors: Shinoda Mao , Yamamoto Kenichiro
Published: December 2023

We introduce a new class of piecewise monotonic maps, called generalised mod one transformations, which include all

(
α
,
β
)

and generalised

β

-transformations, and prove that all transitive generalised mod one transformations with positive topological entropy satisfy the level-2 large deviation principle with a unique measure of maximal entropy. This is obtained by our result on the density of periodic measures for more general class of piecewise mototonic maps, which is a partial answer to the open problem posed by Hofbauer and Raith (1998 Fund. Math.
157 221–34); Raith (www.math.iupui.edu/~mmisiure/open/PR1.pdf).
Miura-reciprocal transformations and localizable Poisson pencils
Authors: Lorenzoni P , Shadrin S , Vitolo R
Published: December 2023

We show that the equivalence classes of deformations of localizable semisimple Poisson pencils of hydrodynamic type with respect to the action of the Miura-reciprocal group contain a local representative and are in one-to-one correspondence with the equivalence classes of deformations of local semisimple Poisson pencils of hydrodynamic type with respect to the action of the Miura group.
A diffusive SIS epidemic model with saturated incidence function in a heterogeneous environment
*
Authors: Gao Daozhou , Lei Chengxia , Peng Rui , Zhang Benben
Published: December 2023

In this paper, we propose a diffusive susceptible-infected-susceptible epidemic model in a spatiotemporally heterogeneous environment. We consider a saturated incidence function of the form

S
I

m
+
S
+
I

, where m is a nonnegative function. When there is a positive disease-induced mortality rate everywhere, we demonstrate that the disease will always become extinct and the susceptible population will stabilize at zero or a positive constant. In the case where the disease-induced mortality rate is negligible, we examine the model in a time-periodic and spatially heterogeneous environment and establish the threshold dynamics between disease extinction and persistence in terms of the basic reproduction number. Under certain conditions, we show the global attractivity of both the disease-free equilibrium and endemic equilibrium by constructing appropriate Lyapunov functions. Moreover, we determine the spatial distribution of the disease when the diffusion rate of the susceptible or infected population (or both) is sufficiently small. Our findings suggest that the presence of a saturation effect reduces the transmission risk, allows for the total population size to have a substantial impact on disease dynamics, and may significantly alter the spatial distribution of the disease under certain circumstances.
ETU-Net: edge enhancement-guided U-Net with transformer for skin lesion segmentation
Authors: Chen Lifang , Li Jiawei , Zou Yunmin , Wang Tao
Published: December 2023

Objective. Convolutional neural network (CNN)-based deep learning algorithms have been widely used in recent years for automatic skin lesion segmentation. However, the limited receptive fields of convolutional architectures hinder their ability to effectively model dependencies between different image ranges. The transformer is often employed in conjunction with CNN to extract both global and local information from images, as it excels at capturing long-range dependencies. However, this method cannot accurately segment skin lesions with blurred boundaries. To overcome this difficulty, we proposed ETU-Net. Approach. ETU-Net, a novel multi-scale architecture, combines edge enhancement, CNN, and transformer. We introduce the concept of edge detection operators into difference convolution, resulting in the design of the edge enhanced convolution block (EC block) and the local transformer block (LT block), which emphasize edge features. To capture the semantic information contained in local features, we propose the multi-scale local attention block (MLA block), which utilizes convolutions with different kernel sizes. Furthermore, to address the boundary uncertainty caused by patch division in the transformer, we introduce a novel global transformer block (GT block), which allows each patch to gather full-size feature information. Main results. Extensive experimental results on three publicly available skin datasets (PH2, ISIC-2017, and ISIC-2018) demonstrate that ETU-Net outperforms state-of-the-art hybrid methods based on CNN and Transformer in terms of segmentation performance. Moreover, ETU-Net exhibits excellent generalization ability in practical segmentation applications on dermatoscopy images contributed by the Wuxi No.2 People’s Hospital. Significance. We propose ETU-Net, a novel multi-scale U-Net model guided by edge enhancement, which can address the challenges posed by complex lesion shapes and ambiguous boundaries in skin lesion segmentation tasks.
Model of opinion dynamics caused by information pressure in multi-agent system with stochastic activation of links
Authors: Savitskaya N E , Fedorova T A
Published: December 2023

The dynamic properties of a modified nonlinear noisy voter model on a square lattice are studied in the paper. The introduced modifications are as follows. First, the changes of the binary variable (opinion) at the voters (agents) are caused by avalanche-like perturbations of the system. Secondly, the structure of inter-agent links is not static. Its temporal evolution is due to a new characteristic of the agent called ‘activity’. It determines the probability for the agent to be linked with its nearest neighbors at a given time moment. In addition we introduce a binary variable that changes randomly in time (an ‘external opinion’). According to the proposed rules for opinion changes, an agent that unlinked to neighbors changes its opinion to a current value of the external opinion, regardless of the opinions of other agents. A linked agent can copy the opinion of its neighbor during an avalanche process. Analytically and numerically, we show that the agents’ ‘activity’ distribution and the time-averaged value of the external opinion completely determines the mode of opinion dynamics. The phase diagram for the model under consideration is obtained. In the case of large values of averaged agents’ ‘activity’ the system switches between two consensus states spending the most of time in the consensus with shared opinion corresponding to the prevailing value of the external opinion. For small value of averaged ‘activity’ the system tends to the state where the opposite opinions coexist, but agents predominate with opinion corresponding to sign of the time-averaged value of the external opinion. We demonstrate that the resulting model reflects the main features of the behavior of real multi-agent systems where the external information inflows into the system and, spreading among agents, drives opinion dynamics.
Singlet quantum phases of the frustrated spin-1/2 ladder with ferromagnetic (F) exchange in legs and alternating F-AF exchange in rungs
Authors: Chatterjee Monalisa , Kumar Manoranjan , Soos Zoltán G
Published: December 2023

Ladders with 2N spins-1/2 and singlet (S = 0) ground states are studied numerically using exact diagonalization and density matrix renormalization group (DMRG) calculations. The curvatures E
″(s) of states with the lowest energy E(s) at spin s = S/N ≤ 1 are obtained in the thermodynamic limit. All states have E
″(s) > 0 in two phases, one with strong F exchange J

F
in rungs, the other with strong F exchange J

L
in legs. The Dimer phase with frustrated F exchanges has one or more states with E
″(s) < 0. All three phases have finite gaps to the lowest triplet state. The ladder at J

F
→ ∞ is adiabatically connected to the spin-1 Heisenberg AF chain, and at J

L
→ ∞ to the J
1 − J
2 model.
Shear horizontal wave dispersion in two phase magneto-electro-elastic material loaded with viscoelastic fluid layer
Authors: Singh Ravindra , Prasad Surendra
Published: December 2023

In the present work, an exact analytical approach has been used to study the dispersive behavior of the shear horizontal (SH) wave in magneto-electro-elastic (MEE) material loaded with a viscoelastic fluid. Complex dispersion equations are derived in the cases of electric short magnetic short (ESMS), electric short magnetic open (ESMO), electric open magnetic short (EOMS), and electric open magnetic open (EOMO) boundary conditions by solving the equilibrium equations of MEE material and the Stokes equation of viscoelastic fluid. To validate the present outcomes, the MEE material is changed into piezoelectric and piezomagnetic materials by taking some theoretical assumptions and the outcomes are matched with preexisting results. Effect of volume fraction, wave frequency, substrate thickness and thickness of the fluid layer on phase velocity and attenuation of SH wave have studied. This study may find its applications in better understanding of the surface acoustic wave devices incorporated with viscoelastic fluid layer.
A 3D simulation model to study all-inorganic CsPbX3 (X = Br and I) perovskites-based light-emitting diodes with different hole-transporting layers
Authors: Mozaffari Samaneh , Ghorashi Seyed Mohammad Bagher
Published: December 2023

The development of numerical models is essential for optimizing perovskite light-emitting diodes (PeLEDs) and explaining their physical mechanism for further efficiency improvement. This study reports, for the first time, on a detailed device modelling of an all-inorganic perovskite LED consisting of CsPbX3 (X = Br and I) as light emitting layer (LEL) with different hole transporting layers (HTLs), employing COMSOL Multiphysics simulation package. Therefore, a 3D simulation model is served to investigate the appropriate HTLs that meet the design requirements of a PeLED in terms of band off-set engineering. For this purpose, a series of all-inorganic halide perovskites with different HTLs such as PEDOT: PSS, CuSCN and MoO3 are simulated under the same theoretical settings, and the performances of LEDs are compared with each other. This is done through studying their electronic properties using current density–voltage (J-V) curves and internal quantum efficiency (IQE) measurements. The results obtained from the J-V curves reveal that all the CsPbBr3-based samples with different HTLs exhibit the same turn-on voltage (V
on) of approximately 4.2 V, while this value increases to 5.8 V for the CsPbI3-based samples. Compared with the PeLEDs based on CsPbI3, the PeLEDs based on CsPbBr3 indicate lower V
on due to the formation of shorter charge carrier injection barriers at their interfaces. Furthermore, among the various simulated structures, the highest IQE is obtained for perovskite CsPbI3-based LED with MoO3 HTL (5.21%). The effect of different parameters on the performance of the proposed configurations are also investigated, and it turns out that the thickness of LELs and lifetime of charge carriers have a decisive role to play in the efficiency of PeLEDs. This theoretical study not only successfully explains the working principle of PeLEDs but also clearly shows researchers how to produce high-performance LEDs in the laboratory by knowing the physical properties of materials and accurately adjusting energy band alignments.
Identification of slow waves in the evolution of KHI near the Venusian ionopause
Authors: Yang Yang , Wang Xiang-Li , Yuan Huaxuanyu , Khan Saleem , Lin Mai-Mai
Published: December 2023

The MHD slow waves in the evolution of Kelvin–Helmholtz instability (KHI) near the Venusian ionopause has been identified by using the magnetohydrodynamics equations. The diagnosis of slow waves utilizes two criteria: the phase speed and the ratio of density oscillation to the velocity oscillation. With the speed of sound greater than Alfvén speed, the phase velocity of slow waves along the initial magnetic field is approximately equal to Alfvén speed. For slow waves, the ratio of the density oscillation to the velocity oscillation along the initial magnetic field is independent of the angle between wave vector and the magnetic field. The data from the side of low-density were analyzed around the KH vortex. The numerical simulation results show that there are slow waves in the induced magnetosphere near the magnetopause of Venus. We also note that during the nonlinear growth stage, the parallel oscillations contribute approximately 76% ∼ 93% to the wave energy. This work will provide more clues that the KHI is a possible source of slow waves observed near Venus-like planets.
The solution of stochastic evolution equation with the fractional derivative
Authors: Duan Yubo , Jiang Yiming , Wei Yawei , Zhou Jie
Published: December 2023

In this paper, we consider the stochastic evolution equation driven by the Gaussian noise with white time and colored space, where the noise coefficient is the Marchaud fractional derivative. The key idea is that we transform our model into a stochastic space-fractional equation by taking the Marchaud fractional derivative, and then use Chaos expansion to prove the mild solution. There are three main results in this paper. First, we apply Chaos expansion to obtain the existence, uniqueness and Lyapunove exponent of the solution of the transformed equation. Second, we prove that there exists an unique mild solution of the original equation, the approach is taking the fractional integral operator into the transformed equation. Finally, we explore Hölder continuity of the mild solution.
Efficacy of argon cold atmospheric pressure plasma jet on hospital surface decontamination and its impact on the surface property
Authors: Das Sarthak , Mishra Biswajit , Mohapatra Sarita , Tripathi Bijay P , Kar Satyananda , Bhatt Satyendra
Published: December 2023

The emergence of antimicrobial resistance has become a major contributor to healthcare-associated infections. Recently, the cold atmospheric pressure plasma jet (CAPJ) discharges have garnered attention of the researchers globally for their novel antimicrobial property. This research evaluated the effectiveness of an in-house developed CAPJ on the inactivation of multidrug-resistant (MDR) E. coli and S. aureus artificially inoculated over stainless steel and aluminium test surfaces. A greater than ∼5 log10 reduction of E. coli, whereas reduction of ∼3.4–4.6 log10 for S. aureus on the test surfaces was achieved on 180 s CAPJ exposure. Extremely low D- values (in the range of ∼27–63 s) were recorded for both isolates. In addition, this study assessed the impact of repeated CAPJ exposure on surface property, by replicating the process of hospital surface decontamination. Surface properties such as wettability, roughness, and elemental composition varied non-linearly on repetitive Ar CAPJ exposure on test surfaces. It was observed that the identified gas-phase species such as excited atoms (Ar I, and O I), positive ions (NO+, O2
+, OH+, O+, N2
+, Ar+, etc), negative ions (N2O2
−, N2O3
−, NO3
−, NO2
−, etc), radical RONS (OH•), and non-radical RONS (O I, NO+, OH+, N2O3
−, NO3
−, NO2
−, etc) would contribute to bacterial load reduction on the test surface along with any alteration in surface characteristic. There may be chemical and physical processes involved in the above activity. This investigation into understanding the effects of CAPJ surface decontamination on surface properties would aid in determining its potential applications in healthcare settings.
Dark matter capture in celestial objects: treatment across kinematic and interaction regimes
Authors: Leane Rebecca K. , Smirnov Juri
Published: December 2023

Signatures of dark matter in celestial objects have become of increasing interest due to their powerful detection prospects. To test any of these signatures, the fundamental quantity needed is the rate in which dark matter is captured by celestial objects. Depending on whether dark matter is light, heavy, or comparable in mass to the celestial-body scattering targets, there are different considerations when calculating the capture rate. Furthermore, if dark matter has strong or weak interactions, the physical behaviour important for capture varies. Using both analytic approximations and simulations, we demonstrate how to treat dark matter capture in a range of celestial objects for arbitrary dark matter mass and interaction strength. We release our calculation framework as a public package available in both Python and Mathematica versions, called Asteria.
Supercooling in radiative symmetry breaking: theory extensions, gravitational wave detection and primordial black holes
Authors: Salvio Alberto
Published: December 2023

First-order phase transitions, which take place when the symmetries are predominantly broken (and masses are then generated) through radiative corrections, produce observable gravitational waves and primordial black holes. We provide a model-independent approach that is valid for large-enough supercooling to quantitatively describe these phenomena in terms of few parameters, which are computable once the model is specified. The validity of a previously-proposed approach of this sort is extended here to a larger class of theories. Among other things, we identify regions of the parameter space that correspond to the background of gravitational waves recently detected by pulsar timing arrays (NANOGrav, CPTA, EPTA, PPTA) and others that are either excluded by the observing runs of LIGO and Virgo or within the reach of future gravitational wave detectors. Furthermore, we find regions of the parameter space where primordial black holes produced by large over-densities due to such phase transitions can account for dark matter. Finally, it is shown how this model-independent approach can be applied to specific cases, including a phenomenological completion of the Standard Model with right-handed neutrinos and gaugedB - Lundergoing radiative symmetry breaking.
Influence of extraction voltage on electron and ion behavior characteristics
Authors: Xu 徐 Ao 翱 , Gan 甘 Pingping 娉娉 , Shi 石 Yuanjie 元杰 , Chen 陈 Lei 磊
Published: December 2023

The characteristics of the extracted ion current have a significant impact on the design and testing of ion source performance. In this paper, a 2D in space and 3D in velocity space particle in cell (2D3V PIC) method is utilized to simulate plasma motion and ion extraction characteristics under various initial plasma velocity distributions and extraction voltages in a Cartesian coordinate system. The plasma density is of the order of 1015 m−3–1016 m−3 and the extraction voltage is of the order of 100 V–1000 V. The study investigates the impact of various extraction voltages on the velocity and density distributions of electrons and positive ions, and analyzes the influence of different initial plasma velocity distributions on the extraction current. The simulation results reveal that the main reason for the variation of extraction current is the space-charge force formed by the relative aggregation of positive and negative net charges. This lays the foundation for a deeper understanding of extraction beam characteristics.
Dynamic Reactive Power Compensation Optimization Strategy for Distribution Networks with Distributed Generators and Energy Storage Systems
Authors: Lv Dongfei , Liu Wenan , Kong Xiangqing , Song Yanshan , Zhang Xingyong , Ma Tao , Zhang Xinsheng , Liu Hongchen
Published: December 2023

To balance the output and load dynamic changes of distributed power generators (DG) and energy storage systems (ESS), a demand-side response-based dynamic reactive power optimization (RPO) strategy for distribution networks (DN) is proposed. This strategy adopts a phased optimization method to coordinate and optimize different types of reactive variables within the same period. By adjusting the states of parallel capacitor banks (SCBs) on load voltage transformers (OLTC), DGs, and ESS inverters, the RPO of the DN is carried out. Based on the characteristics of the model, an improved particle swarm optimization algorithm (IPSO) is used to solve different types of variables, and an IPSO based on tent chaotic mapping and levy flight strategy is proposed to improve the efficiency of collaborative solving. The simulation results show that the proposed strategy, considering the change of new energy output and demand side response, can reduce the solution scale while obtaining high satisfaction RPO results.
Reliability Evaluation and Optimization Configuration Method of Network Distribution Side Energy Storage System Based on Machine Vision
Authors: Hou Wenhao , Gao Qiang , Dong Yuebin , Ying Wei , Lv Linying
Published: December 2023

To reduce the motor power allocation error and improve voltage weak node conditions, this paper designed a reliability evaluation and optimization configuration method for network distribution side energy storage system based on machine vision. Firstly, the abnormal operation parameters of the energy storage system are collected and transmitted on-site. The operational reliability monitoring data of the distribution network side serves as the foundation for designing the operational reliability evaluation algorithm for the energy storage system on the same distribution network side. This algorithm further enables the optimal configuration of the energy storage system. The experimental comparison results demonstrate that upon implementation of the methods of this paper, the motor power allocation error is less, and the lowest is only 0.17 kW. Meanwhile, the fluctuation is relatively flat, and the range is between 0 kW and 0.46 kW. The improvement of weak voltage nodes is good, the voltage load is significantly decreased, and the minimum voltage load is only 5 kW, which proves that the design method of this paper has a certain application value.
A Security-constrained Unit Commitment-based Optimal Battery Usage Pattern Model
Authors: Hu Yaping , Hu Rong , He Yubin , Wen Zhaoxin , Zhang Honglue , Zhu Songming , Zhang Shiling
Published: December 2023

This paper discusses multiple strategies of security-constrained unit commitment (SCUC)-based optimal battery usage pattern models to drive the charging and discharging of different batteries and help the operation cycles satisfy their preferences according to battery characteristics. Previous studies mainly focus on either battery storage integration as a controllable resource into the grid with high penetration of renewable energy, or battery degradation costs as additional terms in the objective function of SCUC. In comparison, this paper first considers whether battery operation cycles satisfy their preferences according to specific battery characteristics. It discusses a full charging/discharging strategy for Ni-Cd batteries, which have a memory effect and prefer deep cycles. Then, the paper explores a shallow cycle strategy for Lithium-ion, lead acid, and Ni-H batteries, which have no memory effect and prefer shallow cycles for long service life. Subsequently, it is extended to a hybrid strategy when batteries with/without memory effects are at the same node. The proposed model minimizes the total operation cost of SCUC while including the penalties for battery usage strategies. The original problem is a mixed integer non-linear programming (MINLP) one, and then it can be mathematically converted into a mixed integer linear programming (MILP) one. Consequently, the models with multiple strategies are tested through IEEE 6-node power system. Computational results show that, compared to the base case without any strategy, the proposed optimal battery usage pattern approaches have an advantage in driving Ni-Cd batteries toward deep cycles, guiding Lithium-ion batteries towards shallow cycles, and improving the flexibility of performance with hybrid applications.
Generalized Turbine Model Based Analysis and Simulation of Ultra-Low Frequency Oscillation of Hydropower Units
Authors: Li Jinzhao , Liu Mosi , Zhang Yihui , Meng Xuanren
Published: December 2023

The occurrence of ultra-low frequency oscillation (ULFO) events in the power grid has a significant number of hydropower units in recent years. Considering this aspect, relevant studies have shown that the turbine model has an important impact on the ULFO behavior of hydropower units. Based on the study of the generalized turbine model, the flow factor closely related to the inherent parameters of the turbine and the variation of the generating flow is defined in this paper. The ULFO model of the hydropower unit with full consideration of the flow factor is established. Based on the frequency characteristics of the system and the Routh stability criterion, the mechanism of the influence of the flow factor on the ULFO behavior of the hydropower unit is analyzed. The simulation results of single-machine and multi-machine systems show that, compared with the ideal turbine model, the generalized turbine model considering the flow factor can increase the stability margin of the system. It can provide greater damping torque and restrain the ULFO behavior of hydropower units. The flow factor is larger, and the suppression effect of the ULFO is more obvious.
Application of Big Data Water Distribution Technology in T Block of Q Oilfield
Authors: Sun Simian
Published: December 2023

With the extension of oilfield development time, a large amount of production data has been accumulated in the oilfield water injection development process, which brings great challenges and opportunities to the adjustment analysis, diagnosis, and optimization of oilfield development [1]. Based on geological static data, historical data such as production and monitoring at both ends of injection and production, and using big data and deep learning methods, this paper forms a big data analysis method for water injection optimization with the mode of “finding key layers of key wells, implementing key monitoring and deciding the best scheme”. Good results have been achieved in guiding the adjustment of single well water quantity in Block T of Q Oilfield. Eight water injection adjustment schemes have been deployed on-site, 16 intervals have been adjusted, and the daily water injection has been adjusted from 136 cubic meters to 120 cubic meters. After adjustment, the accumulated oil in the connected oil well stage has increased by 262.3 tons, and the production decline in the well area has been effectively controlled, which provides new technologies and new ideas for the dynamic development adjustment of the oilfield.
Assessment of the Applicability of PV/T Electric Heating System for the Storage of Crude Oil
Authors: Bao Yongjie
Published: December 2023

There are still some doubts about whether the solar photovoltaic/thermal (PV/T) system is applicable for the practical heating system of crude oil storage although there has been a lot of research work on PV/T and heating technology in the oil field. Due to the uneven distribution of solar radiation and uncertain thermal property of crude oil, the amount of energy provided and demanded is hard to evaluate. In this study, an electric heating system based on PV/T is proposed to be applied for the storage of crude oil. By establishing the mathematical model of the system, the energy supply capacity of PV/T and the heat demand of stored crude oil in typical seasons in Xinjiang are predicted by numerical method. The applicable scheme is discussed. This study may promote the application of PV/T heating systems in oil fields.
Research on Vibration Damping Analysis of UHV Suspended Converter Valve Model
Authors: Zhang Changhong , Lin Sen , Li Hongyuan , Yang Xu , Li Weiguo , Lv Jinzhuang , Lu Hai , Peng Xiang , Huang Jiajie
Published: December 2023

The UHV (ultra high voltage) suspended converter valve is hinged to the top of the valve hall, so the equipment has a long structural period, the suspended converter valve is displaced under the action of earthquakes, and the valve tower is susceptible to damage due to interaction with the important equipment connected to it. The high cost, large size, and weight of the real type of UHV suspended converter valve make it difficult to carry out shaking table test studies of the real type of equipment. In this paper, a numerical model of a UHV-suspended converter valve scaling device and its damping structure model are established, and a damping analysis study with damping at the top of the converter valve model is carried out. The analysis showed that the maximum displacement of the converter tower was 136.3 mm under the action of a 0.4 g El-Centro earthquake. With horizontal damping at the top, the maximum displacement of the converter tower is 62.9 mm, a reduction of 53.9% compared to the undamped case. This study proposes a vibration damping design for UHV suspended converter valve, laying the foundation for subsequent shaker test studies of the scaled-down model vibration damping structure of the UHV suspended converter valve and the productization of vibration dampers for the equipment.
Research on Online Gas Volume Monitoring Technology of Intelligent Gas Relay
Authors: Wang Jian , Zhu Mengzhao , Zhu Wenbing , Gu Zhaoliang , Wang Xuelei
Published: December 2023

The gas relay is the main non-electrical protection device of the transformer, which plays an important role. Traditional detection methods can not reflect the gas relay level, and there will be gas relay false alarms in operation and maintenance. Firstly, the working principle of the gas relay was analyzed, and a non-conductive capacitance sensor was proposed to realize the real-time monitoring of gas volume in the gas relay. Then, a new online monitoring scheme for intelligent gas relays was constructed through the selection analysis and optimization design of the gas protection module and liquid-level measurement module. Based on the changing state of gas volume in the gas relay, a more accurate and timely fault diagnosis of the power transformer was realized, and the prototype processing was completed. Finally, the feasibility of the volumetric testing method was verified by comparing the two conditions of different liquid-level heights and different ambient temperatures. The proposed method is of great significance for discovering the latent faults of transformers and realizing the condition monitoring of oil-immersed power transformers, which ensures the safety of power grid equipment and personnel.
Research on the influence of the connection and withdrawal of a 35 kV bypass system on the power quality of transmission lines
Authors: Zhang Guoxin , Li Muxuan , Chen Jianxin , Zhang Jianfeng , Li Zhengping , Huang Keyi , Huang Jiaming , Deng Qiangwei , Liu Gang
Published: December 2023

Uninterrupted power supply maintenance has become a trending issue with the increasing reliability requirements for 35 kV power transmission. The bypass operation holds significant importance in 10 kV and 100 kV power transmission maintenance. However, research on live maintenance of a 35 kV bypass system remains scarce and requires urgent supplementation. Therefore, this paper aims to determine the feasibility of live operation for the 35 kV bypass system by studying the impact of its connection and disconnection on the voltage and current of the transmission lines. The existing 35 kV bypass live maintenance system is analyzed and studied concerning the operational process. When the bypass system is connected or disconnected during the maintenance of transmission lines, it may cause changes in the voltage and current, which could affect the safety of power transmission. To address this phenomenon, the paper performs calculations and analysis for different scenarios, including moments of varying voltage amplitudes in the lines and different maintenance cable lengths in the bypass system. Through theoretical analysis and simulation, a comprehensive study of voltage and current variations in two different scenarios of transmission lines has been conducted during the simulation process, including equivalent capacitance and initial conditions for the transmission lines and bypass systems, enabling the simulation of the switching process. Based on calculations and analysis, this paper presents a safety assessment of live operation in the 35 kV bypass live maintenance system.
Study on the Maximum Outgoing Line Count of 750 kV Substations and Exploration of a Bus Short-circuit Current Suppression Method
Authors: Ding Yujie , Zhao Jinchao , Fu Guobin , Yang Kaixuan , Zhao Huanbei , Zhao Dongning
Published: December 2023

With the development and construction of new power systems, the power grid structure is becoming increasingly interconnected, and the issue of short-circuiting currents in UHV systems will gradually manifest over the next five years. Existing measures for short-circuit current control typically involve using standby units, lines, and main transformers. However, conventional measures are gradually unable to meet the control requirements, necessitating strict control of the network topology during the planning phase and the exploration of new technologies and methods to keep pace with the evolving era. This paper studies the maximum outgoing line count of 750 kV substations, providing theoretical references applicable to practical operations for planning departments. A conceptual method based on fast-switching technology to suppress the current during a short circuit at the 750 kV voltage level is proposed, establishing the groundwork for the practical implementation of high-speed switching technology in the 750 kV voltage-level power grid.
MTPA Control for PMSM Velocity-specified Position Tracking Based on the Principle of Backstepping Control
Authors: Sun Yiming , Wang Xuping , Yi Fan , Li Buchuan
Published: December 2023

In this paper, a control method based on the backstepping control is proposed to address the issues of uncontrollable speed and complex PI parameter tuning in the traditional PID position control of PMSM. By comparing with id=0 control, MTPA control enables the IPMSM to maximize the utilization of reluctance torque. The dq current relationship under MTPA control is established using a formulaic method. Based on this, a position, speed, and current backstepping controller is designed, which adds a degree of freedom to the speed control during the position control process while ensuring the stability of the control system. Simulation results demonstrate fast dynamic response, small steady-state error, and minimal parameter adjustments, thus verifying the correctness and effectiveness of this method.
Active Distribution Network Reactive Power Optimization Based on an Improved Genetic Particle Swarm Optimization Algorithm
Authors: Gou Shuai
Published: December 2023

As the distributed generation is gradually connected to the distribution network, it will lead to an increase in node voltage deviation and network loss. The active distribution network reactive power optimization approach based on an improved genetic particle swarm optimization algorithm is proposed in this paper to increase voltage quality and system efficiency. First, a reactive power optimization model for active distribution networks that has the least possible active power loss and voltage variation is developed. Then, the genetic idea is applied to the particle swarm optimization algorithm to improve it and address the issues of the long iteration time of the genetic algorithm and the tendency of the particle swarm optimization algorithm to settle into local optimal solutions. Finally, the enhanced genetic particle swarm optimization algorithm described in this paper is validated using the enhanced IEEE-33 node system. The findings indicate that this strategy can significantly shorten computation times while also increasing calculation precision.
A Tuning-free Fault Detection Method for Distribution Network Based on PMU Data and Random Matrix Theory
Authors: Hu Jiaxin , Xue Guiting , Han Zhaoru , Liu Changjiang , Xie Zhiguang
Published: December 2023

The increasing penetration of renewable energy sources has significantly altered the fault characteristics of distribution networks with distributed generators (DGs). The fault current is limited as the emerging solar plants normally connect to the grid via inverters. And the operating patterns of the system have become more diverse and complex. The traditional pre-tuned protection and fault detection methods are facing substantial challenges. This paper proposes a centralized fault detection scheme based on the random matrix theory (RMT) that utilizes synchronous phasor data from the distribution-level phasor measurement unit (PMU). Firstly, data normalization and resampling techniques construct the operating state matrix (OSM). Then the mean spectral radius (MSR) is calculated and used for fault detection without the complex tuning according to the operation state of the system. Finally, the faulty section is determined by comparing the features from different sub-group of the PMUs according to the topology partition. A multi-feeder distribution network is modeled in PSCAD and used to verify the proposed method.
Study of Tunnel Support Methods Based on RMR and Q-System Methods at Kerinci Merangin Hydropower Jambi Province
Authors: Saputra A , Azikin B , Husain R
Published: December 2023

Excavation of tunnel construction at the Kerinci Merangin Hydropower in Jambi Province is a complex job, because it will use the tunnel as a waterway which will always be faced with unstable conditions. One of the way to deal with instability is to classify the mass and determine the type of support on the roof and walls using empirical methods. The parameters in rock mass classification include mapping the structure, physical and mechanical properties of the material. Empirical analysis was carried out using the Rock Mass Rating (RMR) classification and the Q-System to determine the condition of the rock mass in the tunnel and determine the type of support that will be used and in accordance with the rock mass class. The rock mass classes in the study area of STA 8+869, 8+872 and 8+879 based on the RMR classification are included in rock class III, namely rocks that have moderate conditions (fair quality rock mass) and rock class IV, namely rocks that have poor conditions (poor quality rock mass). Meanwhile, the rock mass class based on the Q-System includes very poor rock mass.

The recommendation for supporting the tunnel face according to RMR in the study area is to use a combination of rockbolt, shotcrete and wiremesh supports, while the support recommendation according to the Q-System uses a combination of rockbolt and shotcrete supports.
Trip Distribution and Modal Choice in the Taman Mini LRT Station Area
Authors: Jumardi  , Wunas Shirly , Jinca M. Yamin , Natalia Venny Veronica
Published: December 2023

The surrounding Taman Mini LRT station boasts a diverse range of land uses, primarily characterized by residential zones, interspersed with dynamic activity hubs such as tourist attractions, shopping malls, and hospitals. The prevailing issue in this area relates to persistent traffic congestion, stemming from the overreliance on private vehicles, inadequate public transportation infrastructure, disjointed intermodal connections, and the lack of seamless integration between transportation modes and activity centers. This study endeavors to comprehensively analyze pedestrian and vehicular movement in the periphery of the Taman Mini LRT station. This analysis is pivotal in assessing the current mobility landscape. Notably, the intensity of activity within a particular land use directly correlates with its ability to draw vehicular traffic, consequently leading to prolonged waiting times for pedestrians at crosswalks. Employing a four-step model, this research methodically defines pedestrian and vehicular flow within the region. This model incorporates output distribution of trips and origin-destination graphs. Additionally, stated preference techniques are employed to discern respondents’ inclinations when making travel decisions. This involves evaluating key factors like travel time, fares, frequency, accessibility level, comfort, and safety – categories that significantly influence their preferences when selecting between LRT and other transportation modes.
Development of Sustainable Integrated Transit Area in Gorontalo Province, Indonesia
Authors: Lihawa Eriyanto , Jinca Muhammad Yamin , Hamzah Baharuddin , Syarif Edward
Published: December 2023

Transportation integration is the integration of air, rail and land transportation modes with the aim of improving transportation performance more efficiently and effectively. The development of transit areas is important in order to realize a sustainable transportation system. Isimu Terminal in Gorontalo Province is a gateway to access to various modes of mass public transportation that serve inter and intra-provincial transportation. This research aims to evaluate the existing conditions of the Isimu terminal based on the evolution of the implementation of transit area development according to the categories: seamless mobility, sustainable neighborhood and optimum growth. This research is qualitative deductive. Primary data was obtained through in-depth interviews with station users and direct observation. Secondary data is obtained through institutional surveys to relevant parties. The result the integration of services between Djalaludin airport and Isimu terminal does not seem to be optimally connected and the loading and unloading of goods outside the terminal is visible. However, this area has the prospect of functioning as an intermodal connectivity node with the planned infrastructure development of the train station, Djalaludin airport, and Isimu terminal, and as further suggestions this area can be developed into an integrated transit area and transhipment node.
The Influence Of Variations In Soaking Time Of Rice Husk Charcoal Briquettes On Its Performance
Authors: Suluh S , Bethoni Frans Robert , Lazarus Risa , Simon Christof Geraldi , Johan Chendri , Salo Lery Afriany
Published: December 2023

Rice husk is one of the biomass wastes from agriculture which is used as an alternative energy source in the form of briquettes. These briquettes are used as fuel in aluminum stoves. This study aims to analyze the performance of rice husk charcoal briquettes at various times of immersion in kerosene. The research method was carried out using experimental methods by testing rice husk charcoal briquettes on five variations in soaking time, namely 0 minutes, 5 minutes, 15 minutes, and 20 minutes, after testing on an aluminum stove alternately with the process of boiling water. The results showed that the highest flame temperature, ignition duration, ability to boil water, and highest thermal efficiency were 798% at 120 minutes, 24 liters, and 69.88% at 20 minutes of immersion.
Evaluating Coastal Area Suitability and Ecological Carrying Capacity in Topejawa Village, South Sulawesi
Authors: Nurjayanti  , Hatta Muhammad , Tuwo Ambo
Published: December 2023

Marine and coastal tourism has rapidly emerged as promising sectors with the potential to drive sustainable regional development. Achieving the status of a sustainable tourist destination requires adherence to specific criteria, particularly concerning the ecological carrying capacity of tourism activities. This study aims to evaluate the suitability and carrying capacity of beach tourism in Topejawa Village, Takalar Regency, South Sulawesi, Indonesia, focusing on recreation and swimming activities. Data were collected from eight strategically located observation stations along the beach area from March to August 2022. Using the Tourism Suitability Index (TSI), we assessed ten parameters to evaluate the beach’s physical condition. Additionally, we conducted an analysis of the Ecological Carrying Capacity (ECC) to determine the maximum number of visitors that the tourist area can sustainably accommodate for recreation and swimming activities. Our findings indicate that Topejawa beach area’s stations I, III, and IV were classified as ‘suitable’ with TSI values ranging from 1.8 to 2.1 across all stations. The ecological carrying capacity analysis revealed that the beach can accommodate up to 1,257 individuals per day for recreation and 15,171 for swimming activities. We recommend the period from March to November for beach tourism due to favorable weather conditions. These results demonstrate the significant potential of Topejawa Village for sustainable ecotourism development, emphasizing the importance of ecological carrying capacity assessments and sustainable tourism practices. As coastal tourism continues to thrive, this study provides valuable insights for the responsible management and growth of Topejawa’s beach recreation tourism industry.
Analysis Of NOx, SO2, PM10, & CO Emission Loads From Motorized Vehicle at Collector’s Road Makassar City Using Tier 2 Method
Authors: Savirah Nurul Auliah MA , Aly Sumarni Hamid , Harusi Nurul Masyiah Rani
Published: December 2023

The biggest factor in the global reduction in air quality in large cities is the transportation industry. This is due to the molecules that gasoline, the fuel used in the transportation sector, emits, including carbon monoxide (CO), nitrogen oxide (NOx), sulfur dioxide (SO2), and CO2 (carbon dioxide), as well as hydrocarbons (HC), which are sources of carbon dioxide. of emissions of air pollutants An imbalance results from the rising motorized vehicle sales from year to year combined with poor traffic conditions. In urban locations, several collector roads—the hub of community activity—often encounter congestion, especially during rush hours. Because of the pollution these motorized vehicles produce, the congestion they induce has a negative effect on the environment. This study aims to determine the daily and yearly emission loads for the parameters of NOx, SO2, PM10, and CO produced by motor vehicles with three types of vehicles, namely motorcycles (MC), Light Vehicles (LV), which are divided into the Sedan category, Minibus, Taxi, Public Transportation, then Heavy Vehicles (HV), which are divided into Pick-up, Jeep, micro bus, big bus, 2 axles truck, and 3 axles trucks categories, on Collector Street in Makassar City utilizing the Tier 2 method and show the form for mapping the distribution of NOx, SO2, PM10, and CO emissions from motor vehicles on Collector Street in Makassar City using the Geographic Information System application. The findings indicated that Jalan Hertasning produced the highest emission load from the NOx, SO2, PM10, and CO parameters. This is because of the significant role that Hertasning Road plays in Makassar City’s urban road network, which results in a high volume of daily vehicle traffic on this road section. The CO parameter, which accounts for 104041.57 tons of the total emission load from motor vehicles on Jalan Hertasning, per year.