Operations Reference Research Articles

Performance measurement of organic tea supply chain with supply chain operation references (Case study of active tegal subur farmer group, Kulon Progo)

Tegal Subur Aktif Farmer Group is one of the organic tea producers located in Menoreh Hills, precisely in Nglinggo, Pagerharjo, Samigaluh, Kulon Progo. The efforts carried out by this farmer group include the procurement of tea ingredients, the provision of production facilities, the cultivation and maintenance of tea plants, the processing of agricultural products and trade in general. Processed organic tea products, such as green, black, yellow, and roasted, are produced. Farmer groups have uncertain orders that can only be fulfilled partially, which can still affect customer satisfaction. In total, there are 95.39% of uncertain orders that can be fulfilled in the period August 2021 – March 2022. This is related to production planning with actual production caused by uncertain or regular supply of raw materials. If the collection of raw material supply is still carried out, it causes cost losses in collecting raw materials. The Tegal Subur Aktif Farmer Group has never measured its supply chain performance. If measurement is not carried out, supply chain performance may develop slowly. This study aims to measure the organic tea supply chain's performance and determine which indicators need improvement. This research uses the Supply Chain Operation References (SCOR) and Analysis Hierarchy Process (AHP) methods. Based on the data processing carried out, by measuring supply chain performance with Supply Chain Operation References (SCOR) and Analysis Hierarchy Process (AHP), the supply chain performance of the Active Tegal Subur Farmer Group can be improved.

Pengukuran Kinerja Rantai Pasok Pada Industri Karet Remah dengan Pendekatan SCOR (Supply Chain Operations Reference)

One of the pivotal aspects of a company lies in its supply chain. The company must effectively and efficiently manage their supply chains to support production quality, achieve organizational goals, and ensure customer satisfaction. This research aims to determine the key performance indicators (KPIs) for the crumb rubber processing industry and provide suggestions for improving its supply chain performance. Supply chain performance measurement was conducted using the Supply Chain Operations Reference (SCOR) model in conjunction with the Analytical Hierarchy Process (AHP) method to determine the weights of the KPIs. The research found that the overall supply chain performance score for the crumb rubber company was 84.92, categorizing it as "Good." However, among the 26 Key Performance Indicators (KPIs) identified, three indicators (i.e. production of defective products, consumer complaints, and returns of defective products) fell into the "Poor" category. Hence, it is crucial for crumb rubber industry stakeholders to address these three criteria to enhance supply chain performance.

Fast and Reliable Network RTK Positioning Based on Multi-Frequency Sequential Ambiguity Resolution under Significant Atmospheric Biases

The positioning performance of the Global Navigation Satellite System (GNSS) network real-time kinematic (NRTK) depends on regional atmospheric error modeling. Under normal atmospheric conditions, NRTK positioning provides high accuracy and rapid initialization. However, fluctuations in atmospheric conditions can lead to poor atmospheric error modeling, resulting in significant atmospheric biases that affect the positioning accuracy, initialization speed, and reliability of NRTK positioning. Consequently, this decreases the efficiency of NRTK operations. In response to these challenges, this paper proposes a fast and reliable NRTK positioning method based on sequential ambiguity resolution (SAR) of multi-frequency combined observations. This method processes observations from extra-wide-lane (EWL), wide-lane (WL), and narrow-lane (NL) measurements; performs sequential AR using the LAMBDA algorithm; and subsequently constrains other parameters using fixed ambiguities. Ultimately, this method achieves high precision, rapid initialization, and reliable positioning. Experimental analysis was conducted using Continuous Operating Reference Station (CORS) data, with baseline lengths ranging from 88 km to 110 km. The results showed that the proposed algorithm offers positioning accuracy comparable to conventional algorithms in conventional NRTK positioning and has higher fixed rate and positioning accuracy in single-epoch positioning. On two datasets, the proposed algorithm demonstrated over 30% improvement in time to first fix (TTFF) compared to conventional algorithms. It provides higher precision in suboptimal positioning solutions when conventional NRTK algorithms fail to achieve fixed solutions during the initialization phase. These experiments highlight the advantages of the proposed algorithm in terms of initialization speed and positioning reliability.

Evaluation of Blockchain Technology for Supply Chains using an Integrated Fuzzy Cognitive Map-QFD Methodology

The rapid advancement of technology has made it imperative for supply chains to adapt to the changing landscape. Blockchain technology holds immense potential to transform supply chain processes, but the challenge lies in identifying the most suitable blockchain characteristics to meet the various performance indicators of a supply chain. To overcome this challenge, this study aims to prioritize the most critical blockchain characteristics in a supply chain. The study adopts a two-stage Quality Function Deployment (QFD) methodology to rank blockchain characteristics based on supply chain and software requirements. The methodology evaluates the supply chain performance indicators using the Supply Chain Operations Reference (SCOR) model and software needs using the International Organization for Standardization (ISO) software quality characteristics. After determining the problematic SCOR and ISO software-related metrics, the study utilizes the QFD Stage 1 to obtain the weights of ISO software characteristics and employs the Fuzzy Cognitive Map (FCM) to determine the most crucial blockchain characteristics for QFD Stage 2. The results of this study show that the top priorities for blockchain characteristics in a supply chain are smart contract functionality, privacy, transaction per second, tokenization, security, permissioned network, scalability, cost, modularity, and licensing, in order of importance.

An Efficient DC-AC Power Integration Model for Single-Phase Systems, Simulated in MATLAB

In the face of growing clean energy demands, this study presents a model for integrating Direct Current (DC) sources into the existing Alternating Current (AC) grid. The model is based on a single-phase system where a DC source is added. A converter, designed using the synchronous reference frame, is proposed to address integration issues. This converter allows for the control of both active and reactive power using a dq reference frame. A Proportional-Integrator (PI) controller is chosen for this purpose. To generate the necessary operational references, a Phase-Locked Loop (PLL) is used. An LCL filter is also incorporated based on its performance quality. The entire model is simulated in MATLAB, and the output obtained confirms the model’s ability to control both active and reactive power when integrating DC with AC and T. This work significantly contributes to the efforts of integrating clean energy into our existing grid systems.

Research on unbalanced characteristics of axial-varying eccentric rotor based on signal demodulation

In the presence of non-uniform loads, rotor misalignment emerges as a prevalent fault in permanent magnet synchronous motors (PMSMs), leading to the manifestation of an axial-varying eccentric air–gap. Considering the three-dimensional (3D) nature of magnetic flux under axial-varying eccentric fault, 3D finite element (FE) analysis method was used in this paper. Then, the electromagnetism simulations were conducted to calculate the magnetic flux density and unbalanced magnetic pull (UMP). With the signal demodulation algorithm based on principal component analysis (DPCA), the frequency modulation of various signals from simulation and experiment was extracted. Furthermore, based on the modulation features, the relevance among magnetic flux density, UMP, and vibration acceleration was established with shaft frequency as the link. The coupling of magnetic field and vibration level shown in results was analysis, which provide important theoretical and engineering references for the safe operation of PMSM system and the exact identification of rotor tilting faults.

Risk analysis and assessment of underwater glider mission failure using Dynamic Bayesian Network method

The Autonomous Underwater Glider (AUG), with its extended operational endurance, encounters various uncertain risks during diverse mission tasks. Therefore, conducting dynamic risk analysis is crucial for implementing subsequent decisions and improving equipment safety. This paper combines Fault Tree Analysis (FTA) and Dynamic Bayesian Network (DBN) to develop a customized dynamic risk assessment method for AUG task failure under multiple risk factors. Firstly, preliminary risk factors are identified by FTA using existing experimental data. Next, transformation rules are constructed to map FTA into a basic DBN model. Then, parameters such as conditional probabilities are determined through logic gates and parameter learning, and the proposed model is validated based on axioms. Finally, key risk factors are identified based on actual failure data. The research results indicate that the key risk factors leading to AUG task failure are progressive abnormalities such as biofouling and ocean current disturbance. The method proposed in this paper can achieve dynamic risk assessment, providing strong references for operators in making decisions for subsequent tasks.

Measurement of Seaweed Supply Chain Performance in UD Bangkitg

This research aims to measure the performance of the supply chain at UD Bangkit, a trading business engaged in the production and distribution of seaweed. Supply chain performance measurement is carried out using the Supply Chain method Operations Reference (SCOR) which includes five main dimensions: reliability, flexibility, cost, assets and responsiveness. The research results show that measuring UD Bangkit's Performance Attributes using the SCOR and AHP approach obtained a value of 51.58, it can be said that supply chain performance is in the average category. Based on the SCOR calculation, the lowest final attribute value is the performance value attributes reliability and metrics are perfect order fulfillment of 72 with a performance value of 9.36, and a performance value attributes responsiveness and its metrics Order Fulfillment Cycle Time is 48 with a performance value of 7.2. The highest value was obtained for Asset attribute Management, with a result of 18.83.

Research on the Deformation Mechanism of Railway Subgrade under Buried Strike–Slip Fault Dislocation

With the gradual densification of China’s railway network, more and more railways are inevitably crossing active fault zones. Creep dislocation and stick–slip dislocation of the fault zones can lead to uneven deformation and cracks in the railway subgrade, threatening the sustainability of the railway. Therefore, a model test and numerical simulation were used to analyze the deformation mechanism and sustainability of the subgrade and foundation induced by a strike–slip fault dislocation in a flat site under different angles between the subgrade and fault strikes. The test and simulation results show that (1) under the influence of strike–slip fault dislocation, the horizontal direction of the subgrade appeared to have an S–shaped displacement. The top surface of the subgrade appeared to have a vertical settlement. Further, tension–shear cracks and compression crush zones appeared on the subgrade’s surface. (2) When the angle between the fault and subgrade strikes increased, the subgrade’s uneven deformations induced by fault dislocation first decreased and then increased. The angle between the main tension–shear crack on the top surface of the subgrade and the fault strike showed a trend of increasing and then decreasing. In addition, the compressive stress along the subgrade strike decreased, while the tensile stress along the subgrade strike gradually increased. (3) The tension–shear cracks in the subgrade and foundation were spiral and converged to the basement strike–slip fault along the depth direction. This study provides a reference for the safe operation and sustainability of railways near faults.

Novel differential pumping system with extended sampling range: Design and application in the EAST tokamak

A novel differential pumping system (DPS) with an adjustable sampling rate has been developed and implemented in the Experimental Advanced Superconducting Tokamak (EAST). This system is equipped with a high-resolution quadrupole mass spectrometer (QMS), covering a mass range of 1–16 atomic mass units (AMU), alongside a conventional QMS with a broader range of 1–200 AMU. The DPS features a dynamic pressure sampling capability from 10−2 to 105 Pa, utilizing a gas dosing valve and an angle valve, enabling a wide gas sampling ratio range of 10−9 to 3 × 10−2. The high-resolution QMS (QMG700) is adept at directly quantifying the partial pressures of deuterium and helium within mixtures, while the conventional QMS (RGA200) offers indirect measurement of D2 partial pressures above 2 × 10−5 Pa, complemented by direct wide-range mass analysis. During the EAST tokamak campaigns of 2023 and 2024, the DPS was effectively utilized for glow discharge cleaning (GDC) at a pressure of 3 Pa and ion cyclotron wall conditioning (ICWC) at approximately 3 × 10−3 Pa, accurately distinguishing deuterium pressure from the helium environment in the wide pressure range of vacuum vessel. Moreover, the DPS was successfully employed to trace the vacuum leak location in EAST campaign with a pressure of up to hundreds Pa. This DPS is a key tool for gas ingredient analysis and leak detection in the EAST campaigns, providing a valuable reference for the vacuum operation of future fusion reactors.

Development of ergo-refined operator's workplace and biophysically actual cost-benefit analysis of riding type self-propelled machines with special reference for female operators.

Female agricultural workers contribute to 37% of the total agricultural workforce in India, however, most self-propelled machinery is designed for male agricultural workers. The primary objective was to determine the impact of the ergo-refined operator's workplace on various aspects of operator performance and comfort, including actuating force, posture, and physiological parameters. Experiments were carried out in real field conditions using a full factorial randomized design. Twelve female operators participated in the study, and measurements were taken for control lever actuating force, operator posture, heart rate, and other relevant parameters. The ergo-refined operator's workplace intervention resulted in significant reductions in actuating force for various control levers, angles of joints, working heart rate (WHR), oxygen consumption rate (OCR), muscle load, and whole-body vibration (WBV) acceleration. These reductions were observed under different operating conditions. The findings suggest that the ergo-refined operator's workplace is effective in enhancing operator comfort and reducing physical strain during the operation of riding type self-propelled machines. It contributes to improved safety, comfort, and operational efficiency for operators working in field conditions. ANOVA and MANOVA analyses confirmed the positive impact of operating conditions and engine speed on the measured parameters when using the ergo-refined operator's workplace.

Supply chain performance measurement incorporating green factors using the supply chain operations reference on a fertilizer company

Supply chain performance measurement incorporating green factors using the supply chain operations reference on a fertilizer company

ANALYSIS OF SUPPLY CHAIN PERFORMANCE AND ADDED VALUE OF TEMPEH IN MATARAM CITY

Supply chain performance measurement presents a valuable opportunity to enhance and advance supply chain management practices across various industries, including the tempeh agroindustry. The research was aimed at analyzing the structure and performance of the supply chain, as well as the added value of the tempeh agroindustry in Mataram city. The study utilized a descriptive method that involved interviewing several respondents. Collected data was analyzed using the Supply Chain Operation Reference (SCOR) method version 9, and Hayami Model Added Value Analysis. The results indicated that the stakeholders involved in the agroindustry supply chain in Mataram city were soybean importers in Java, local soybean supply agents, tempeh agroindustry entrepreneurs, and tempeh retailers. The study found that the tempeh agroindustry supply chain performance attained superior performance in the Reliability, Flexibility, Responsiveness, and Asset attributes. On the other hand, the Total Supply Chain Cost attribute recorded poor performance. Processing one kilogram of soybeans into tempeh yielded an added value of IDR. 9,280.82, with an added value ratio of 43.56%, and is categorized as moderate.

Study of the Measurement Method on the Dynamic Stress and Pressure of Model Pump-turbine Splitter Blades

Abstract The operation conditions of the pump-turbine are changed frequently and are worse than the conventional turbine. The operation stability of the pump-turbine is more focused with the incremental unit capacity and the pump-turbine runner diameter. The research of the measurement method for the dynamic stress and the pressure of the model pump-turbine splitter runner blades is performed to evaluate the stress and pressure distribution under the various operation conditions, it is optimized for the turbine mechanical and hydraulic computation, the operation references are provided for the prototype pump-turbine also. In this paper, the measurement positions of the blades are determined based on the hydraulic CFD and mechanical computation, the measurement method of dynamic stress and pressure of model pump turbine-runner splitter blades is studied.

Research on hump characteristics improvement of low-mid specific speed high-power centrifugal pump

Abstract The hump phenomenon is a typical hydraulic instability of centrifugal pump. The hump curve is easily found on H-Q characteristic curves of centrifugal pump at low flow conditions. Hump phenomenon causes large vibration and noise and affects the unit stability of star-up process. The impeller model with specific speed ns=100 was used an initial impeller for the high-power centrifugal pump to be developed, and the meridian flow channel keep unchanged. The impeller geometry, the blade profile, blade exit edge, wrap angle, inlet blade angle were optimized to improve hump characteristics. The 3D pump model with the initial and optimized impeller were simulated to obtain the H-Q characteristic curve. The numerical simulation results show that the inlet secondary reflux is significantly weakened, energy characteristics and hump margin of the optimized impeller are obviously improved compared with the initial impeller. The optimized impeller was also tested on the model test system to verify the hump margin. The test results demonstrate that the optimized design considerably improve the centrifugal pump’s hump margin. The results of simulations and model tests verified that impeller optimization was a suitable and efficient way to enhance the hump characteristics. The result provides design reference for long-term safe and stable operation of low-mid specific speed high-power centrifugal pump.

Performance analysis of supply chain for construction materials at high rise building project based on Supply Chain Operations Reference Method: A case study

Abstract Supply chain management is an approach to implementing lean construction efforts to minimize construction project problems, such as cost overruns, project delays, and disputes. Implementation of supply chain management is necessary, especially in the procurement of materials. However, there is a need to measure performance during the implementation. Results of measurement can show the extent to which the project operates and use it as a benchmark to determine the end impact of a project. This study’s purpose is to measure of supply chain performance with the supply chain operation reference (SCOR) method and use the analytical hierarchy process (AHP). Compile data using an observation with scoring form based on standards adoption, categories, and SCOR metrics through key performance indicators (KPI) and structured interviews with the contractor to validate. Limited to the study is the supply chain of ready-mix concrete materials. The AHP method give the weight of the output value of the KPI. The results of the KPI measurements from the contractor’s perspective are that one indicator is still at a low value, which is a cycle time for fulfilling orders. An overall result of 84.83 from the measurement KPI suggests a “good” performance category.

Biological fermentation pilot-scale systems and evaluation for commercial viability towards sustainable biohydrogen production

Featuring high caloric value, clean-burning, and renewability, hydrogen is a fuel believed to be able to change energy structure worldwide. Biohydrogen production technologies effectively utilize waste biomass resources and produce high-purity hydrogen. Improvements have been made in the biohydrogen production process in recent years. However, there is a lack of operational data and sustainability analysis from pilot plants to provide a reference for commercial operations. In this report, based on spectrum coupling, thermal effect, and multiphase flow properties of hydrogen production, continuous pilot-scale biohydrogen production systems (dark and photo-fermentation) are established as a research subject. Then, pilot-scale hydrogen production systems are assessed in terms of sustainability. The system being evaluated, consumes 171,530 MJ of energy and emits 9.37 t of CO2 eq when producing 1 t H2, and has a payback period of 6.86 years. Our analysis also suggests future pathways towards effective biohydrogen production technology development and real-world implementation.

An Improved Back Propagation Neural Network Based on Differential Evolution and Grey Wolf Optimizer and Its Application in the Height Prediction of Water-Conducting Fracture Zone

Given that the conventional back propagation neural network (BPNN) easily falls into the local optimal solutions, resulting in poor prediction accuracy, an improved BPNN based on the differential evolution and grey wolf optimizer (DEGWO) is proposed, the so-called DEGWO-BPNN. The prediction of the water-conducting fracture zone (WCFZ) height is significant for mine safety operations. A total of 104 sample data are trained and 25 sample data are tested to identify the optimal prediction model. Five evaluation indexes are selected to assess the prediction performance of the models quantitatively. Finally, the DEGWO-BPNN model is applied to a specific engineering case. The main conclusions are as follows: (1) Mining height, mining depth, coal seam dip, panel width, and ratio of hard rock as the main factors affecting the WCFZ height are selected. The topology structure of the model is defined as ‘5-12-1’; (2) the bias between the predicted value and the actual value of the training samples is smaller with an average error of 2.39. Test samples further validate the prediction precision through evaluation indexes. The values of MAE, RMSE, MAPE, and R2 are 2.3952, 3.4674, 5.3148%, and 0.99077, respectively. The prediction accuracy is 94.6852%; (3) ‘Mining Code’, MLR, BPNN, and GWO-BPNN models are treated as the comparison groups. The comparative analysis shows that the prediction performance of ‘Mining Code’ is the worst, while that of DEGWO-BPNN is the best, and it outperforms other algorithms and statistical approaches; (4) the prediction of WCFZ height in the 11601 panel is in line with the actual value. The prediction error of the DEGWO-BPNN model is lower than that of the comparison models. As such, the DEGWO-BPNN model can be well applied to the prediction of WCFZ height and is suitable for coal mines with different regional geological conditions. It can provide a valuable reference for mine safety operations.

Establishing marine protected areas in the southern ocean, lessons for the BBNJ agreement

This paper first gives a brief overview of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR)’s struggle to establish Antarctic Marine Protected Areas (MPAs). The paper then addresses the question: what lessons can countries learn from CCAMLR’s experience in establishing high seas MPAs under the Biodiversity in Areas Beyond National Jurisdiction (BBNJ) Agreement? The paper finds that the final text of the BBNJ Agreement did largely reflect CCAMLR’s experience when it comes to MPAs. This is particularly so with respect to 1) clarification of the relationship between conservation and use; 2) the interpretation and application of a science-based precautionary approach; and 3) consensus-based decision-making process. The paper concludes that the insights CCAMLR provides for navigating geopolitical tensions between major powers is an important reference for the future operation of the BBNJ Agreement.

Multi-Time-Scale Low-Carbon Economic Dispatch Method for Virtual Power Plants Considering Pumped Storage Coordination

Low carbon operation of power systems is a key way to achieve the goal of energy power carbon peaking and carbon neutrality. In order to promote the low carbon transition of energy and power and the coordinated and optimized operation of distributed energy sources in virtual power plants (VPP), this paper proposes a framework for collaborative utilization of pumped storage–carbon capture–power-to-gas (P2G) technologies. It also constructs a multi-time scale low carbon economic dispatch model for VPP to minimize the internal resource operation cost of VPP in each time period. During the intraday scheduling stage, the day-ahead scheduling results as the planned output and the energy flow is then dynamically corrected at a short-term resolution in the framework. This allows for the exploration of the low-carbon potential of each aggregation unit within the virtual power plant. The results of the simulation indicate that the strategy and model proposed in this paper can effectively encourage the consumption of renewable energy sources, promote the low-carbon operation of power system power, and serve as a valuable reference for the low-carbon economic operation of the power system.