Science & Technology Asia

Base-𝛽 Representations and Irreducibility of Polynomials over Any Imaginary Quadratic Field

Narakorn Rompurk Kanasri, Phitthayathon Phetnun — Fri, 29 Mar 2024 00:00:00 +0700

Let 𝐾 be an imaginary quadratic field whose ring of integers 𝑂𝐾 is a Euclidean domain. In the earlier work, the so-called base-𝛽 representation for nonzero elements of 𝑂𝐾 was constructed and the irreducibility criterion for polynomials in 𝑂𝐾 [𝑥] was established,
namely if 𝜋 = 𝛼𝑛 𝛽 𝑛 + 𝛼𝑛−1 𝛽 𝑛−1 + · · · + 𝛼1 𝛽 + 𝛼0 =: 𝑓 (𝛽) is a base-𝛽 representation of a prime element 𝜋 ∈ 𝑂𝐾 and the digits 𝛼𝑛−1 and 𝛼𝑛 satisfy some natural restrictions, then the polynomial 𝑓 (𝑥) is irreducible in 𝑂𝐾 [𝑥]. A generalization of this criterion was also verified by considering 𝜔𝜋 (𝜔 ∈ 𝑂𝐾 \{0}) instead of 𝜋. In this paper, we extend these results to any imaginary quadratic field 𝐾.

Convergence of Best proximity pair for noncyclic Suzuki’s relatively nonexpansive with numerical simulation

Fri, 29 Mar 2024 00:00:00 +0700

The goal of this research is to examine a Thakur’s iterative approach for a noncyclic relatively Suzuki’s nonexpansive with a projection mapping in the famework of convex uniformly Banach space. Using this iteration as a base, we offer a few sufficient conditions and useful lemma to ensure the convergence of a best proximity pair for a mapping. We also provide a case study to illustrate the main results with numerical simulation for this algorithm.

Forward Jump Random Walk on a Cycle Graph and Its Hitting Time

Rachanai Kaikeaw, Pasin Marupanthorn — Fri, 29 Mar 2024 00:00:00 +0700

This paper presents an investigation into a random walk on a cycle graph with restricted forward movement at most 𝑚 steps, known as the forward jump random walk. The study derives exact formulas for the probability mass function of the arriving state, the hitting time, and its expected value and variance, where those solutions can be expressed in terms of trigonometric sums. These formulas are obtained using a combinatorial method as an alternative to the eigenvector-based approach commonly used.

Spatial Distribution of Drunk Driving Cases in Nakhon Pathom Province

Wichittra Phlicharoenphon, Ornprapa Pummakarnchana Robert — Fri, 29 Mar 2024 00:00:00 +0700

This research study utilized Geostatistics to examine the spatial data on drunk driving incidents in Muang Nakhon Pathom from 2013 to 2017. The study collected data on 685 drunk driving cases and 1,096 Facebook statuses geotagged to entertainment venues. This study aimed to investigate the pattern of drunk driving incidents, analyze hot spots, study the directional distribution of drunk driving cases, and explore the relationship between drunk driving cases and social aspects. The findings revealed that the drunk driving cases were clustered, with the highest number of cases occurring in Sanam Chan sub-district, where alcohol stores and entertainment venues are located. The cases were mostly directed towards the eastern part of Nakhon Pathom, and the study found a positive correlation between drunk driving and geotagged statuses with statistical significance as p-value = 0.05. The outcomes of this research can be used to inform policy-making and decisions related to public posts about drinking-related activities.

Evaluation of Bioactive Composition and Phytochemical Profile of Macroalgae Gracilaria edulis and Acanthophora spicifera from the Banda Aceh Coast, Indonesia

Said Ali Akbar, Muhammad Hasan — Fri, 29 Mar 2024 00:00:00 +0700

This study aimed to examine the metabolite profiles and phytochemical content of Gracilaria edulis and Acanthophora spicifera along the coast of Banda Aceh in Indonesia. The three attributes observed by this study were phytochemical composition, antioxidant scavenging, and in vivo metabolite profile by the use of Gas Chromatography-Mass Spectrometry (GC-MS), antioxidant activity test, and Fourier Transform Infrared (FTIR) characterization, respectively. Extracts from both G. edulis and A. spicifera demonstrated high scavenging capability, with inhibition values of 42.59% and 39.81%, respectively. In both species, the GC-MS methodology was shown to be a quick, sensitive, and trustworthy way to monitor individual components and the entire chemical composition. In G. edulis, there were 29 phytochemical compounds, whereas in A. spicifera, there were 26 compounds. The ethanol extracts of G. edulis and A. spicifera were then subjected to an FTIR spectrum analysis. These findings at 3352 cm-1, 1654 cm-1, and 1019 cm-1 proved that alkanes, alkenes, and hydroxyl groups were present, corresponding to several compounds in the GC-MS measurement results. G. edulis and A. spicifera are potential antibacterial agents; the bioactive compounds conferring this activity are heptadecane, hexadecanoic acid, and other ester derivatives.

Synchronous Colonic Neuroendocrine Tumor and Adenocarcinoma: A Case Report with Literature Review

Naree Pluthikarmpae, Chatchanok Paoin — Fri, 29 Mar 2024 00:00:00 +0700

Multiple primary malignancies are categorized as synchronous and metachronous tumors, depending on the different rules of international institutions. The synchronous occurrence of a colonic neuroendocrine tumor with adenocarcinoma is rare. We present a case involving a synchronous colonic neuroendocrine tumor and adenocarcinoma. Our patient is a 68-year-old male with a positive stool occult blood test from a check-up examination. A biopsy of an unknown location from a colonoscopy revealed a moderately differentiated adenocarcinoma. His whole-abdominal computed tomography (CT) scan showed focal eccentric thickening with solid enhancement of the hepatic flexure colon. The patient underwent a right hemicolectomy. Macroscopic examination revealed an ulceroproliferative mass at the hepatic flexure and a submucosal mass at the cecum. The mass at the hepatic flexure exhibited villous, back-to-back, and cribriform glands composed of columnar cells with some tumor cells floating in extracellular mucin that were positive for CK20 and CDX2 immunostaining, diagnosed as a well-differentiated adenocarcinoma with mucinous features. The mass at the cecum revealed nest, trabecular, and glandular patterns of monotonous cuboidal to polygonal cells that tested positive for synaptophysin, chromogranin A, and CDX2 immunostaining, diagnosed as a well-differentiated neuroendocrine tumor. Many hypotheses have been proposed regarding the pathogenesis of neuroendocrine neoplasms with other primary malignancies. In our opinion, a genetic abnormality of common cell origin might be one of the possible etiologies of our case due to the common endodermal origin and the positivity of CDX2. We recommend that close surveillance for synchronous tumors in patients with colorectal neuroendocrine tumors might be helpful.

In Vitro Fertilization and Embryonic Development of Sargassum polycystum C. Agardh (Phaeophyceae) Under Different Salinity, pH, and Temperature Levels

Jeffersan G. Pada, Jayzon G. Bitacura — Fri, 29 Mar 2024 00:00:00 +0700

Sargassum species are ecologically and economically important resources in marine environments. Recently, they have been subjected to mass cultivation to avoid overexploitation in the wild. Since physicochemical conditions could easily fluctuate in culture settings, this study evaluated the fertilization and embryonic development of Sargassum polycystum under various salinity, pH, and temperature levels. Reproductive organs were subjected to 30 ppt, 35 ppt, and 40 ppt salinity levels, 4.0-5.0, 5.5-6.5, and 7.5-8.5 pH ranges, and 29-30ºC, 34-35°C, and 39-40ºC temperature ranges. Results showed that fertilization and embryonic development of S. polycystum are significantly affected by the different treatments. Increased salinity (40 ppt), increased acidity (pH=4.0-5.0 & 5.5-6.5), and increased temperature (34-35°C & 39-40ºC) caused a significant decline in the fertilization and survival of embryos of S. polycystum. These results will be helpful for the development of better culture conditions for S. polycystum.

The Failure of Repurposing Drug Therapies Based on in vitro and in vivo Studies: A Case Study of COVID-19

Teerachat Saeheng, Juntra Karbwang, Kesara Na-Bangchang — Fri, 29 Mar 2024 00:00:00 +0700

Ineffective selection of therapeutic drugs during an urgent situation leads to failure of COVID-19 treatment in large clinical trials, wasting time and money. We aimed to demonstrate the utility of physiologically-based pharmacokinetic (PBPK)/pharmacodynamic (PD) modeling to support the withdrawal of chloroquine (CQ) and ritonavir-boosted lopinavir (LPV/r) for COVID-19 treatment. The developed whole-body PBPK models were validated against clinical data. Model validation was performed using acceptable methods. The inhibitory effect was calculated to demonstrate drug efficacy. In different clinical trials, various regimens of CQ and LPV/r for COVID-19 treatment were used for simulation. The risk of cardiotoxicity following high-dose CQ administration was assessed. The effect of lung pH on drug concentrations in epithelial lining fluid (ELF) following a high CQ dose and LPV/r was evaluated. The whole-body PBPK models were successfully developed (AAFEs of 1.2-fold). The inhibitory effect (%E) of CQ following high-dose regimens in both ELF and bronchial epithelial cells (BEC) was lower than 2 and 1%, respectively. The corresponding values for the high dose of LPV/r were 40 and 2%, respectively. The risk of prolonged QTc in the population was higher than 20%. In addition, the %E of CQ was increased to 76% at pH 5.6 and decreased to 0.13% at pH 7.5. The change in pH in ELF did not influence LPV/r concentrations. PBPK/PD modeling supports the withdrawal of CQ and LPV/r for COVID-19 treatment as an effective tool for selecting therapeutic drug regimens in urgent situations.

Application of CCME Water Quality Index for Drinking Water Quality Assessment along Kalu Ganga, Sri Lanka

Inoka Batugedara, Indunil Senanayake — Fri, 29 Mar 2024 00:00:00 +0700

Kalu Ganga is considered one of the major rivers in Sri Lanka. The river contributes to drinking water supply, domestic water usage, agriculture, mini-hydropower generation, small-scale industries, and recreation. The present research fills the information gap regarding the water quality status along Kalu Ganga. At the same time, only a few attempts have been made using the Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI) to interpret water quality conditions in Sri Lankan rivers. Therefore, this study attempted (i) to investigate the temporal and spatial variations in drinking water quality along Kalu Ganga and (ii) to calculate the CCME WQI. Herein, July-October (2020) were considered wet months, while January-February (2021) were considered dry months. Altogether, twenty surface water sampling locations were selected, including six locations in the head zone, seven locations in the transport zone, and another seven locations in the deposition zone. In total, thirteen water quality parameters were measured on a monthly basis using standard methodologies; these included temperature, pH, total dissolved solids, electrical conductivity, salinity, dissolved oxygen, biological dissolved oxygen, nitrate, total phosphate, orthophosphate, total alkalinity, total hardness, and chlorophyll-a. CCME WQI was calculated using the total hardness, total dissolved solids, total alkalinity, electrical conductivity, pH, nitrate, orthophosphate, and total phosphate parameters. All sampling locations were categorised as excellent for drinking according to CCME WQI (95-100), with the exception of sampling locations in the deposition zone with fair-good quality (79-80) during the dry months. Overall, the drinking water in Kalu Ganga was categorized as excellent-fair based on the water quality parameters for this WQI calculation. However, saltwater intrusion was observed up to 14km from the river mouth during the dry months. Further studies, including heavy metals and microbial parameters, can further develop the WQI.

Applicability Assessment of Oil Palm Trunk Biochar for Use as Soil Amendment: Morphology, Structure, and Chemical Properties

Ebsan Marihot Sianipar, Sumihar Hutapea, Ernitha Panjaitan, Siti Mardiana — Fri, 29 Mar 2024 00:00:00 +0700

This study was conducted to investigate the quality of biochars derived from oil palm trunk (OPT) based on relative trunk height (bottom, middle, top). The OPT biochars were produced by drum retort kiln with a temperature range of 300-400°C (slow pyrolysis conditions). Morphology, structure, chemical properties and heavy metal content of the OPT biochars were measured in order to assess their suitability for use as a soil amendment. The synthesized carbon was analyzed by X-ray diffraction analysis (XRD). The morphology of the OPT biochars was analyzed by scanning electronic microscopy (SEM) coupled with an energy dispersive X-ray spectrometer (EDX) to identify mineral species on the OPT biochar surface. The analytical methods applied for biochar characterization were proximate analysis and elemental analysis. Characterization of surface functional groups of the OPT biochar was carried out using Fourier transform infrared spectroscopy (FTIR). According to the analysis results, the biochar derived from bottom OPT had the highest intensity peak measured by XRD; it contained 62.05% fixed carbon, 69.21% carbon, and it had the lowest oxygen content at 26.28%. The highest number of pores was found in biochar derived from top OPT. Overall, the biochars had rich macronutrients, numerous functional groups, and low heavy metal content. This study showed the applicability of oil palm trunk biochar for use as a soil amendment for agricultural applications.

Biochemical Properties of Myofibrillar Protein and Gel Characteristics of Surimi from Rohu (Labeo rohita) as Affected by Frozen Storage

Phatthira Sakamut, Katsuji Morioka, Warangkana Sompongse — Fri, 29 Mar 2024 00:00:00 +0700

The effects of frozen storage at -18ºC on the biochemical properties of myofibrillar protein (MF) extracted from rohu (Labeo rohita) surimi, and the gel characteristics of surimi were investigated. Biochemical changes were determined by the Ca²⁺-ATPase activity, total and reactive sulfhydryl (SH) content, and SDS-PAGE patterns. The gel properties were determined by gel strength, water holding capacity (WHC), whiteness, and from observations of the SDS-PAGE patterns and microstructure. Extended frozen storage was found to affect myosin. This was reflected in Ca²⁺-ATPase activity, reactive SH content, and myosin heavy chain intensity, which also decreased as the storage period was extended. This was confirmed by the decreasing of gel strength and WHC, the degradation of myosin heavy chain, and the formation of large protein clusters. The whiteness increased as the frozen storage time increased. This suggested that extended storage at -18ºC caused myosin denaturation, which in turn lead to a change of gel properties.

Application of Fly Ash to Improve Workability, Heat Generation, Autogenous Shrinkage, and Cost-Effectiveness of High Strength Concrete

An Pham-Hoai, Parnthep Julnipitawong, Somnuk Tangtermsirikul, Yusuke Ishii — Fri, 29 Mar 2024 00:00:00 +0700

This study aims to evaluate the full potential of using FA in high strength concrete (HSC) mixtures for relieving the troublesomeness in use of HSC by comparing HSC containing FA with HSC containing silica fume (SF) only and ternary binder HSC containing SF and ground granulated blast furnace slag (GGBS) based on equivalent high strength of 83 MPa and high slump flow of 650mm. In the study, workability, compressive strength, autogenous shrinkage, temperature rise, chloride penetration, and carbonation resistance were tested on nine HSC mixtures with and without FA. Test results reveal that using FA in HSC mixtures reduces their viscosity, particularly in the ternary binder mixtures containing 20% FA and 10% SF. Combining 20% FA with 7% SF in the HSC reduces the maximum temperature measured by the semi-adiabatic temperature rise test. The maximum temperature is equivalent to the HSC mixture with 20% FA or mixture with 30% GGBS and 7% SF in combination. Ternary binder concrete mixtures comprising 20% FA and SF show slightly lower 28-day compressive strength than the SF-only mixtures, but their 91-day compressive strength values are equivalent to those of the SF-only mixtures. Due to the improved microstructures, all HSC mixtures perform well in carbonation and rapid chloride permeability, particularly the ternary binders. In the ternary binder HSC mixtures, although 30% GGBS performs better than 20% FA in terms of compressive strength, utilizing FA in HSC improves concrete performances in terms of viscosity, autogenous shrinkage, heat generation, and rapid chloride permeability as well as cost-effectiveness.

Effect Analysis of Pollutant Distribution on the Flashover Performance of Porcelain and Composite insulator using Finite Element Method

Farah Adilah Jamaludin, Chia Soon Chao — Fri, 29 Mar 2024 00:00:00 +0700

The paper presents the investigation of flashover performance on porcelain and composite insulators by using the finite element-based method. The main focus of this study was to investigate the performance of insulators when operated under pollution since pollution is the leading factor of flashover phenomenon. In terms of the pollution configuration, different methodologies were proposed according to the nature of the insulating material. For porcelain insulators, the assumption based on previous research is that pollution accumulates as a conductive layer covering the surface of the insulator. In contrast, the composite insulator will have particulate matter to indicate the formation of a pollution layer on the insulator surface as the hydrophobic property would provide additional resistance to contamination. The simulation was conducted in finite element-based method software by applying different types of pollution configurations to porcelain and composite insulator surfaces. Evaluation of the simulation results will be based on the evaluation of electric field strength across the insulators surfaces. By comparing the electric field profiles across the insulator’s surfaces, the flashover performances of the insulators can be determined. Based on the evaluation results, the composite insulator shows better performance under pollution conditions, providing a more stable operation and stands as a more economical replacement for porcelain insulators to ensure the sustainability and reliability of the power system.

Analysis of Freight Modal Shift Potential on Railway Infrastructure Development for Cross-Border Trade under the Belt and Road Initiative Strategy

Klairung Ponanan, Sirikarn Chansombat — Fri, 29 Mar 2024 00:00:00 +0700

The Chinese government has developed transport infrastructure rapidly under the Belt and Road Initiative (BRI) strategy. The development of transportation infrastructure has been affected by the transportation aspect of ASEAN countries, especially Thailand. Therefore, this study aims to forecast the freight transportation demand of each mode that will be shifted from the existing transportation mode to the railway mode, specifically in the case of a potential new railway route that can link to the China-Laos railway. A questionnaire was used to collect the data for the 180 samples, which sample group consists of entrepreneurs who are related to freight transportation. Then the Mode Choice Model was generated to forecast freight transportation demand, which is the route that can be connected with the China-Laos railway. The results show that the mode shift of freight transportation is separated into 2 sub-models for the decision-making of entrepreneurs on transportation mode, which consist of (1) entrepreneurs who invest in transportation infrastructure by themselves, and (2) entrepreneurs who do not invest in transportation infrastructure by themselves. The group of entrepreneurs belonging to the (1) sub-model will not change the current transportation mode to rail mode on the railway route due to their investment cost of the infrastructure, which this supposed to be energy products. In the group of entrepreneurs that belongs to (2) sub-model, some entrepreneurs will change the current transportation mode to rail mode on the railway route, which this supposed be to the consumer products.

Two-Sided Disassembly Line Balancing Design with a Soft Computing Technique

Choosak Pornsing, Arnut Watanasungsuit, Choat Inthawongse — Fri, 29 Mar 2024 00:00:00 +0700

The aims of this research are twofold. First, a mathematical model is developed for the problem of two-sided balancing of disassembly lines for medium-sized products. Second, a metaheuristic algorithm is proposed for solving such a problem. The proposed mathematical model attempts to minimize the number of workstations, paired stations, modified index of work relatedness and workload balance between workstations. The proposed model falls in the domain of mixed-integer linear programming, which can be explained by the fact that it is a 𝑁𝑃-hard problem. We have presented the modified particle swarm optimization, which adds the concept of Pareto optimality to include the non-dominated solutions in the elite list. The proposed method is compared with two competing algorithms: the genetic algorithm and the combinatorial optimization with random algorithm on four benchmark instances. The result, which follows the concept of Pareto optimality, shows that our proposed method provides more non-dominated solutions than the competing algorithms. Moreover, the proposed algorithm exhibits better convergence and diversity than the competing algorithms. In practice, this research work could serve as a basis for designing a two-sided disassembly line for a medium-sized product.

Cellulose Extraction from Sisal Fibers and Thermo-Chemical Characterization for Sustainable Industrial Applications

Samir Zidi, Imed Miraoui — Fri, 29 Mar 2024 00:00:00 +0700

The research on cellulose extraction from sisal fibers and its application in industry is an important field of study, especially with regard to the creation of environmentally friendly materials. The aim of this particular study was to utilize natural fiber waste and promote sustainability by extracting cellulose from sisal fibers. Several analytical methods, such as EDX, TGA, DSC, and tensile testing, were used to evaluate the properties of the extracted cellulose fibers. The results show that the extracted cellulose was thermally stable and had good mechanical properties, making it suitable for various industrial purposes. The use of natural fiber waste as an alternative to synthetic materials is receiving increasing attention due to its potential to reduce the environmental impact and promote circular economy practices. This study contributes to the growing body of research on sustainable materials and highlights the potential of using natural fiber waste in industry. Additionally, it provides insights into the potential use of sisal fibers in other areas, such as biodegradable packaging materials, textiles, and medical applications. The development of sustainable materials is crucial in addressing environmental challenges and promoting sustainable development, and this study provides valuable insights into the use of natural fibers as an environmentally friendly alternative to synthetic materials.

Service Life of Reinforced Concrete Structural Members

V. Guru Prathap Reddy, T. Tadepalli, Rathish Kumar Pancharathi — Fri, 29 Mar 2024 00:00:00 +0700

Estimating the remaining service life of a structure is an essential part of bridge management systems (BMS). This involves investigating multiple deterioration mechanisms in concrete via chemical attacks due to chlorides, sulphates, acids, carbonation and other external effects. The influence of materials used in construction, exposure conditions, and maintenance history of the bridge are normally studied for estimating the remaining life. In the present case, an analytical study was performed to understand the deterioration in concrete due to carbonation. Carbonation occurs when carbon dioxide (CO₂) enters into concrete through interconnected pores under humid environmental conditions. The effect of carbonation on the initiation time of corrosion in bridges can be determined based on IRC: SP 60-2002. In the current work, the effect of carbonation on different types of cement -Ordinary Portland Cement (OPC) (Type-1), OPC + fly ash (Type-2), OPC+ silica fume (Type-3), with varied grades (M20 to M50) and types of concrete of different dosage (air entrained and non-air entrained) and rate of carbonation is compared for (sheltered and non-sheltered) and structures with different exposure conditions. It was found that the effect of carbonation on service life is less in the presence of supplementary cementitious materials, while air-entrained concrete is less susceptible to the impact of carbonation than non-air-entrained concrete.

Seismic Performance Evaluation of RC Bridges by IDA of Single-Run ESDOF and ISA

Prakit Chomchuen, Virote Boonyapinyo — Fri, 29 Mar 2024 00:00:00 +0700

This study aims to present the applicability of incremental dynamic analysis (IDA) of equivalent single degree of freedom (ESDOF) and incremental static analysis (ISA) by incremental capacity spectrum method (ICSM) for evaluating the seismic performance of single column bridges. A lateral load pattern that includes higher mode effect for single-run displacement-based nonlinear static analysis to evaluate the lateral behavior of multi-degree of freedom (MDOF) analytical model is proposed. The failure criteria include the interaction of axial force and bidirectional moments, shear failure and column drift limit. The efficiency of the proposed load pattern is investigated through evaluating seismic performance of the typical single column bridge with three different column heights in Bangkok, Thailand. The results show that the different load patterns result in difference capacity and stiffness of ESDOF. The results also show that the IDA of ESDOF with the proposed load pattern can be used efficiently and accurately for all studied bridges compared with IDA of MDOF. Moreover, using IDA of ESDOF for evaluating the seismic performance of the studied bridges can reduce the computational time about 15 times per load case compared with IDA of MDOF. The ISA by ICSM also reduces the computational time because the nonlinear time history analysis is not required for this method. However, the ISA by ICSM shows acceptable results only for the studied bridge with high first-mode participating mass ratio. The results also show that the spectrum acceleration of MDOF at collapse are 0.746g, 1.130g, and 0.461g for the studied bridges with 4.5 m., 6.3 m., and 15 m. column heights, respectively.

Next Generation Heffron-Phillips Model for Damping Power System Oscillations based on a Novel Meta-Heuristic Snake Optimization Algorithm

Niharika Agrawal, Faheem Ahmed Khan, Sheila Mahapatra — Fri, 29 Mar 2024 00:00:00 +0700

Low-Frequency Oscillations (LFO) created due to various disturbances affect the integrity, security, efficiency, and safety of the power system. The traditional Heffron-Phillips (HP) Model of a power system has 6-K-Constants and the state vector is composed of only four state variables. In the present work, a higher-order Synchronous Machine Model 1.1 is used to develop the next-generation HP Model called an Advanced Heffron-Phillips Model (AHPM). There are now 5 state variables and 10 K-Constants including the dynamics of d and q-axis internal voltages. A novel meta-heuristic snake optimization algorithm (SOA) with the key features of exploration and exploitation is used for optimizing the parameters of PSS, TCSC, and Coordinated PSS and TCSC, and the results are compared. The coordinated model based on AHPM produced excellent stability results. The system oscillations died out fastest, with a settling time of less than 2 seconds, and a damping ratio as high as 99.30% is achieved with the coordinated model. Together with the graphical responses, the dominant eigenvalues are mentioned to highlight this notable shift in performance. The system’s power transfer capacity is also improved along with stability. The integration of renewables into the grid creates new stability issues and challenges. This AHPM based on SOA is capable of meeting these challenges. The power grid with AHPM is more efficient, robust, secure, and safe against unpredictable operating conditions with renewables.

Multi-Objective Generation Maintenance Scheduling Using Global Criterion and Lexicographic Methods

Fri, 29 Mar 2024 00:00:00 +0700

Generation maintenance scheduling (GMS) is a power system maintenance model that allows system equipment to provide electricity continuously, while also improving system reliability (SR). However, turning off a distributed generator (DG) for maintenance prevents it from generating power for sale. As a result, revenue that a generation company (GenCo) might potentially receive is decreased. Therefore, reliability and cost outcomes should be considered when planning maintenance. Several studies recommend the GMS model, based on multi-objective problems solved through optimization methods. The global criterion and lexicographic methods, by contrast, are two mathematical approaches individually applied in distinct network topologies, objectives, and constraints. In addition, the coefficient search space, specified as a single constant, is also used in the lexicographic method. This paper uses the GMS model with global criteria and lexicographic methods in the same systems to assess efficiency of multi-objective problem solutions based on cost and system reliability for both methods. Coefficient search space is adjusted for the lexicographic method, depending on the first objective. Based on the IEEE 6 and IEEE 18-bus test networks, a numerical example is investigated. Results indicate that the two methods provide distinct GMS plans for a GenCo to select. If the GMS problem is based on a few objectives, DGs, or loads, the global criterion is preferable to the lexicographic method for mathematical findings. The main objective of coefficient search space settings for the lexicographic method should be adjusted to obtain results close to the main objective.