Operational Mistakes Research Articles

Risk assessment for Na-Zn liquid metal batteries

Background Na-Zn liquid metal batteries, which operate at 600 °C, have recently been proposed as inexpensive stationary energy storage devices. As with any other electrochemical cell, their fabrication and operation involves certain risks, which need to be well understood in order to be minimised. Methods A risk assessment according to ISO 12100 is performed at the cell level for operating Na-Zn cells in the laboratory environment. Hazard identification and risk evaluation are systematically addressed, including a thorough literature review, theoretical calculations and selected experiments. Results Cell overpressure is found to be one of the main risks – and might be caused either by mistakes in battery production (humidity) or operation (over-charge/discharge). In terms of cell housing, the weakest component is clearly the feedthrough. Its failure might lead to the release of hazardous aerosols to the environment. In this context, the candidate electrolyte components LiCl and BaCl2 are especially dangerous, and should therefore be reduced or avoided if possible. Conclusions Overall, Na-Zn cells are expected to reach a very high safety level, similar to state-of-the-art ZEBRA technology, as they are not prone to thermal runaway. However, considering the still low TRL level and open questions concerning the durability of certain parts of their housing, the batteries should preferably be operated under a fume hood.

Systematic optimization of off-grid green hydrogen production systems

In this work a novel mathematical programming formulation is presented for the simultaneous optimal design and operation of standalone, green hydrogen production systems. There is a pressing need to develop, test and commercialize technologies that can contribute in the medium term to our coordinated efforts to combat climate change. The system under study is inherently dynamic due to the stochastic and intermittent nature of meteorological data and there is a likelihood to overestimate its production capacity and economic performance. Failing to identify shortcoming in the design stage can result in expensive operational mistakes that will negatively affect the gathering race to build a massive new hydrogen economy. We present and demonstrate a systematic methodology that could be useful in decarbonizing our energy production systems by optimizing standalone, green hydrogen units and reducing the risk during their commercialization.

Increasing urine nitrification performance with sequential membrane aerated biofilm reactors

This study aimed to investigate whether separating organics depletion from nitrification increases the overall performance of urine nitrification. Separate organics depletion was facilitated with membrane aerated biofilm reactors (MABRs). The high pH and ammonia concentration in stored urine inhibited nitrification in the first stage and therewith allowed the separation of organics depletion from nitrification. An organics removal of 70 % was achieved at organic loading rates in the influent of 3.7 gCOD d−1 m−2. Organics depletion in a continuous flow stirred tank reactor (CSTR) for organics depletion led to ammonia stripping through diffused aeration of up to 13 %. Using an MABR, diffusion into the lumen amounted for 4 % ammonia loss only. In the MABR, headspace volume and therefore ammonia loss through the headspace was negligible. By aerating the downstream MABR for nitrification with the off-gas of the MABR for organics depletion, 96 % of the ammonia stripped in the first stage could be recovered in the second stage, so that the overall ammonia loss was negligibly low. Nitrification of the organics-depleted urine was studied in MABRs, CSTRs, and sequencing batch reactors in fed batch mode (FBRs), the latter two operated with suspended biomass. The experiments demonstrated that upstream organics depletion can double the nitrification rate. In a laboratory-scale MABR, nitrification rates were recorded of up to 830 mgNL−1 d−1 (3.1 gN m−2 d−1) with ambient air and over 1500 mgNL−1 d−1 (6.7 gN m−2 d−1) with oxygen-enriched air. Experiments with a laboratory-scale MABR showed that increasing operational parameters such as pH, recirculation flow, scouring frequency, and oxygen content increased the nitrification rate. The nitrification in the MABR was robust even at high pH setpoints of 6.9 and was robust against process failures arising from operational mistakes. The hydraulic retention time (HRT) required for nitrification was only 1 to 2 days. With the preceding organics depletion, the HRT for our system requires 2 to 3 days in total, whereas a combined activated sludge system requires 4 to 8 days. The N2O concentration in the off-gas increases with increasing nitrification rates; however, the N2O emission factor was 2.8 % on average and independent of nitrification rates. These results indicate that the MABR technology has a high potential for efficient and robust production of ammonium nitrate from source-separated urine.

A bowtie model for fuel gas leakage incidents in an FPSO engine room

Safety and operational costs are of paramount importance in offshore facilities. Efforts to find new ways to reduce operational costs and minimize risks have led to the development of techniques in the field of safety. Routine checks and equipment maintenance are conducted based on either calendar periods or equipment uptime, using conditional monitoring, to prevent malfunctions through preventive maintenance (PM). PM is a key strategy for ensuring the integrity and process safety of safety barriers in offshore facilities. However, due to challenges in modeling dependencies, determining maintenance intervals, and updating belief in operational data, ineffective safety barriers can occur and lead to incidents. Excessive maintenance can also increase the risk of operational mistakes among workers. This study examines safety and operational issues associated with fuel gas leak events caused by various risk factors in Floating Production Storage and Offloading (FPSO) engine rooms using the bow-tie model. Within this context, safety barriers are defined, encompassing both preventive controls and mitigating measures that can be employed to minimize potential risk factors. Furthermore, the study underscores the importance of maintenance intervals for a specific set of safety barriers, necessitating periodic testing using Condition-Based Maintenance (CBM) tools for FPSO units.

Integrity Testing Performance Analysis in Embedded Systems using IDI

Multiple modules that interact with one another to exchange data make up embedded systems. Incorrect resource data exchanged between modules might cause anomalies or mistakes in operation. Resources that interact create dependencies between two modules, such that modifications made to one module's resources will impact modifications made to another module's functionality. Interaction errors between modules are one of the main causes of severe software failures, according to several embedded system investigations, such as those conducted on aerospace or automotive systems. Interaction testing is therefore a crucial step in minimizing risk and reducing interaction errors. When modules interact both directly and indirectly, interaction failures arise. Indirect interactions occur beneath the interface, where a data reliance relationship with resources may lead to an unexpected result

Scenario study on the choice of drilling method for oil wells in the context of the Brazilian pre-salt layer

This work aims to show the techniques and operational procedures that are used on an Offshore Drilling Rig, as well as application on each step of the process to the construction of an oil and gas well to prevent operational mistakes that cause non productive time. In the present work, an analysis regarding on a “Pre-Salt” well-constructed by a conventional drilling method, as well as difficulties encountered due to the method chosen. The results observed on case study show that the correct choose of the drilling method can determine significant advance in the “Pre-Salt” wells, in order to reduce the lost time and not to affect the well construction chronology.

Kembangan Dam Safety Risk Index Sragen Regency

In dam management, in addition to the safety factors of the structure and condition of the dam and the emergency action plan that needs to be prepared, other elements that need to be considered are the operation, maintenance, monitoring and observation activities of the dam. In extreme circumstances, mistakes in dam operations can be fatal. The dam can fail and cause a massive flood that can damage facilities and infrastructure, and even loss of life downstream of the dam. Risk assessment is a way to identify risks that may occur under various conditions, so that the necessary follow-up can be done if the risk is unacceptable. In this study, a risk assessment was conducted to obtain a safety value for the Kembangan Dam located in Karangmalang District, Sragen Regency, Center Java Province. The method used in this research is to use the risk index method. The risk index method assessment parameters are obtained from the initial importance factor of the dam (I dam), the calculation of the total risk index of the dam (IR tot), and the safety value of the dam (N aman). The results showed that the Kembangan dam had an initial importance factor (I dam) of 356.25, a total risk index (IR tot) of 66.618, and a dam safety value (N aman) of 81.3. Thus, it can be concluded that the safety level of the Kembangan dam is included in the Kembangan clause.

Errors of professional activity of transport system operators in conditions of high information load

Introduction. Ensuring traffic safety on the railway network involves the development of complex predictive models that take into account both the state of technology and the influence of the "human factor" in order to minimize the risk of erroneous actions and prevent accidents.
 The study aims to research the mistakes of railway transport operators (using the example of locomotive crew workers).
 Materials and methods. The authors have conducted the study on the basis of analysis of the database of erroneous actions of employees of locomotive crews (2020–2021), submitted by the Research Institute of Railway Transport (according to the agreement on joint scientific cooperation between the Izmerov Research Institute of Occupational Health and Research Institute of Railway Transport).
 Results. The database recorded 104,515 cases attributed to 291 types of erroneous actions with qualitative differences that reflected the degree of risk to the safety of train traffic. The most common categories of violations related to the maintenance of train documentation, errors in locomotive control, non-compliance with the speed limit, disconnection of locomotive safety devices, speeding, brake control violations, violations of the rules of negotiations, the passage of a forbidding signal. In relation to employees who committed violations, the most common disciplinary penalties were identified (analysis of the case in technical classes, deprivation of an employee of a bonus in the amount of 25, 50 and 100%). In a number of cases, several different disciplinary penalties were applied to one employee at the depot for the same violation.
 Limitations. Inability to get access to the protocols of psychophysiological examination of employees of locomotive crews.
 Conclusion. The obtained scientific results allow us to assert that the productivity and safety of the operator's activity correlates with the level of professional training and the mechanisms of its inclusion in the activity. The prospects for further research of the problem of ensuring the safety of locomotive crews' employees consist in a detailed study of the combined effect of factors of the working environment and the labor process in conditions of increasing labor intensity, increasing speeds and volumes of railway transportation. It is necessary to study the ratio and role of such indicators as reliability, professional suitability and readiness of the employee to perform functional duties in the event of an emergency.
 Ethics. The study was carried out on the basis of documents submitted by JSC "Russian Railways". The documents contained the number and typology of mistakes made by employees of locomotive crews in the period 2020-2021. The scientists have conducted the study in accordance with the Ethical principles of anonymity, confidentiality, respect for the rights of the subject of the study, the principles of scientific and impartiality.

Lived Experiences in Family Business Among Business Graduates of a Private Higher Educational Institution in Iloilo City, Philippines

There has been no academic work dedicated to the discovery of the lived experiences of business graduates from a private higher educational institution in Iloilo City, Philippines in their respective family businesses in terms of their daily lives. This phenomenological study was conducted to explore the lived experiences of business graduates of a private higher educational institution in Iloilo City, Philippines who joined their respective family businesses. Moreover, this study intended to describe the profile of the business graduate participants, family business involvement, family relationships, personal and work-related conflicts, and (4) contributions to their family firms. The qualitative research design was employed for this study, specifically phenomenology. Seven participants through purposive sampling voluntarily joined in this phenomenological study after signing the informed consent form. They came from the class of 2017 to 2019 business graduates. The result showed that the seven (7) participants of this study were all business graduates, who were majority males, aged 23-27 years old from a private educational institution in Iloilo City. They had never enrolled in any graduate school programs. The majority graduated last 2019 with three (3) years of working experience. The majority are into retail and hardware supplies. The operational years of their businesses ranged from nine (9) to 55. Almost all were classified as having medium businesses and only one was classified as small. For their family business involvement, they have experienced early involvement in their businesses, they were trusted to manage, and they feel valued. Strong family relationships also emerged among business graduates. They have experienced parental comfort and advice as well as close relationships with their parents. As to the personal and work-related conflicts, they experienced careless operational mistakes, interpersonal work conflicts, emotional challenges, and limited freedom. When it comes to their contributions to the family businesses, they have contributed to the vision and internal control strategies, social media marketing, sales increase, financial clarity, and lessening the workloads of parents. This study can serve as a basis for involving business graduates early in the family business. Employing them can enable them to contribute success factors earlier. Maintaining strong relationships among family members employed in the family firm must be done to avoid personal and work-related conflicts.

Analisis Kesalahan Dalam Penyelesaian Pemecahan Masalah Pada Materi Sistem Persamaan Linear Dua Variabel Di SMP Islam An-Nuur

The purpose of this research is to describe the types of problem-solving errors made by students in solving math problems on the subject of two-variable linear equations. The method used in this study is a qualitative method. This research design uses a case study. The subjects used in this study were class VIII of An-Nuur Islamic Junior High School, Sukabumi City and the subject taking technique used purposive sampling. The data collection technique used is the method of observation, tests and interviews. The data analysis used in this study is data reduction, data presentation, and conclusions. Based on the results of the analysis and calculation recap that has been carried out, procedural errors are greater than procedural errors or computational errors. The Factors that cause students to make mistakes include students often forget to write down what they know and are asked in the questions, students do not know the meaning of the questions, students do not know the steps to be taken, students make mistakes in arithmetic operations, students do not understand the material studied, students are less careful when working on.

Risk mitigation in service industries: A research agenda on container shipping

Shipping lines face various marketing risks, with outcomes that need to be mitigated. A current, serious, example of this has been the COVID19 pandemic and the severe supply chain disruptions that followed it. During such times, unmitigated marketing risks can lead to corporate failure, significant losses, or irreparable adverse impact on a carrier's brand name, due to sailing schedule unreliability. We cast a look at the marketing risks of shipping lines deriving, for instance, from adverse market developments, competitor moves, operational mistakes, unreliability (schedule integrity; supply of containers to customers, etc.), and we propose avenues of risk mitigation. Our methodology includes a combination of literature review and Spherical Fuzzy Theory. Among other conclusions, our results show that it is the ‘unexpected’ and ‘unanticipated’ -e.g., a natural disaster; a war; a tsunami; or COVID19-that poses the greatest risk to carriers: Intense competition amongst them, geared to short-term profit maximization, and coupled with the fine-tuning of capacity management within alliances, does not allow them the luxury of affording built-in buffers or slacks that could ‘absorb’ the unexpected. Not unexpectedly therefore, COVID19 has been the greatest risk factor of all times, mitigated –quite profitably one should add—by the joint capacity management of global shipping alliances.

A hybrid learning frame work for recognition abnormal events intended from surveillance videos

The need for a monitoring system has grown as a result of rising crime and anomalous activity. To avoid unusual incidents, the common man initiated video surveillance of important areas, which was then passed on to the government. In typical surveillance operations, surveillance devices create a vast volume of data that must be manually analysed. Manually handling huge data sets in real time results in information loss. To prevent abnormal incidents, the actions in sensitive areas can be properly monitored, evaluated, and alerted to the appropriate authorities. Previous deep learning-based activity identification methods have appeared, but the findings are inaccurate, and the proposed Hybrid Machine Learning Algorithms (HMLA) incorporate two detection methods for surveillance videos like as Transfer Learning (TL) and Continual Learning (CL). As a result, the suspicious activity in the video may be missed. Consequently, numerous image processing and computer vision technologies were used in activity detection to decrease human effort and mistakes in surveillance operations. Activities in sensitive areas can be properly monitored and evaluated to avoid unusual incidents, and the appropriate authorities may be alerted. Hence, in order to decrease human error and effort in surveillance operations, activity recognition embraced a variety of image processing and computer vision technologies. In this present work, the capacity has constraints that impact recognition accuracy. Consequently, this research paper presents a HMLA based technique that uses feature extraction using multilayer (Long Short Term Memory) LSTM, Convolutional Neural Networks (CNN), and Temporal feature extraction using multilayer LSTM to improve identification accuracy by 96% while requiring minimal execution time. To show the superior performance of the proposed hybrid machine learning technique, a standard UCF crime dataset was utilised for experimental analysis and compared to existing deep learning algorithms.

BrightBox — A rough set based technology for diagnosing mistakes of machine learning models

The paper presents a novel approach to investigating mistakes in machine learning model operations. The considered approach is the basis for BrightBox – a diagnostic technology that can be used for analyzing prediction models and identifying model- and data-related issues. The idea is to generate surrogate rough set-based models from data that approximate decisions made by monitored black-box models. Such approximators are used to compute neighborhoods of instances that undergo the diagnostic process — the neighborhoods consist of historical instances that were processed in a similar way by rough set-based models. The diagnostic process is then based on the analysis of mistakes registered in such neighborhoods. The experiments performed on real-world data sets confirm that such analysis can provide us with efficient and valid insights about the reasons for the poor performance of machine learning models.

Reinforcement Learning for Improving Flappy Bird Game

Currently, Artificial Intelligence becomes popularity among the human daily life, like games, Internet and so on. Authors has shown that in the game filed the Artificial Intelligence always have better performance than human beings, so in this article, the author wants to use AI to carry out on an old- fashion fame called Flappy Bird. This study aims to determine the specific method why AI has better performance than human beings. In this context, the author based on the process of experiments: It mainly used reinforcement learning model (Acting based on feedback from the environment, through continuous interaction with the environment, trial, and error, to ultimately accomplish a specific purpose or to maximize the overall benefits of the action) and supervised learning model (the process of making the machine learn a large amount of sample data with labels, training a model and making the model get the corresponding output according to the input) to improve the Flappy Bird and both two method are belonging to the machine learning. In addition, this study alters the layout of the game, including pipe, appearance of agent, and background of the game in order to make a more fashionable game. Furthermore, this study increases the number of agents, which makes it easier for agent to achieve higher score. Last but not the least, author establish a archive point, which means if the player face operation mistake and lead to game over, they bird will relive before passing the last pipe.

Lessons Learned to Avoid Formation Damage Development During Waste Slurry Injection Operations

The injection of oil and gas wastes produced during the exploration and production phases have been proven to be an effective technique towards achieving zero discharge. However, several challenges are associated with the injection of slurry into an underground formation. The most common challenge during waste slurry injection (WSI) is the loss of well injectivity and pre mature formation damage due to a poor engineering and operational design. For the WSI operation, near wellbore formation damage is one of the major risk and is created by the injected solids. The real time injection monitoring of the ongoing operations is important to make amends to the injection procedure in order to avoid the formation damage and ensure the well longevity. Three different case studies are presented to highlight the operational mistakes that caused a significant formation damage in injectors in Eagle Ford, Haynesville, and Permian Basin shale plays of Texas, United States. Certain guidelines depending on the monitoring results are provided like modifying the slurry rheology, injection pressure, injection strategy etc. that are helpful in maintaining the injectivity. The presented case studies show that the wells with good monitoring program maintained its injectivity during its operation compared to the other wells that lost its injectivity sooner. The paper discusses the importance of injection monitoring and steps necessary to maintain the injectivity and perform a healthy WSI operation.

Making Thoughts Visible through Formative Feedback in a Mathematical Problem-Solving Process

This study aims to elicit the role of formative feedback in the development of students in a mathematical problem-solving process. For this purpose, the study's primary process is to investigate the development of elementary school students (aged 10 to 11) through feedback given during a problem-solving process. While visually engaged in the sub-processes expressing a problem situation and describing their thinking structures in writing, three different dimensions are addressed: communicating visually what they understood from the problem; expressing their thoughts about solution; and creating explanations regarding their solution process. The six-week embedded mixed method study reveals that students' explanations of their thinking processes developed towards the expectations. They were able to depict the problem and the relationships involved in the problem more clearly in their drawings to understand the problem. They made fewer mistakes in mathematical operations.

BGP Anomaly Detection Using Association Rule Mining Algorithm

An anomaly is the occurrence of an exception that affects network security. The requirement for abnormality detection in a network is Anomaly detection, which detects and removes anomalous flow from the network. The Border Gateway Protocol (BGP) is the most common external Gateway Protocol used to communicate with autonomous systems to share routing and reachability information. This protocol's abnormal behavior may be caused by a variety of factors, including inadequate provisioning, malicious attacks, traffic or equipment issues, and network operator mistakes. BGP was built on the assumption of trust, and as a result, it has been hacked numerous times over the years. Code Red I is one well-known assault that targets BGP networking and produce abnormalities in its operation. These attacks were utilized as the dataset for training the model using network traffic data. The goal of this study is to detect the events that triggered an anomaly in the BGP during a time, as well as to detect an anomaly from the BGP throughout that time interval using the training dataset model. We present real association rule mining for BGP anomaly detection in the Intrusion Detection System (IDS).

Breeding and conservation of Luciola cruciata Motschulsky, 1854 (Coleoptera: Lampyridae) larvae in forests near chemical factories

The number of fireflies in Japan has decreased with the development of cities and industries. As a first step toward the regeneration of an environment for fireflies, we report an attempt to breed aquatic firefly larvae. Focusing on the operational stability of equipment used, we use a safety evaluation method like that employed in petrochemical plants. The death of larvae is a major risk in the operational safety of firefly larvae breeding. The larval death scenario is analyzed and clarified using fault tree analysis, demonstrating that reducing operational mistakes in monitoring water flow and temperature conditions contribute most to the reduction of the probability of larval death. An experiment simulating water supply stoppage to estimate the permissible time for a response once the water temperature rose is reported. A firefly larval breeding system equipped with an alarm function for prompting emergency responses is constructed. Fireflies, including mature larvae, are successfully bred and the effectiveness of this system is demonstrated by comparing it with a conventional system. The superiority of the breeding system of this study is indicated by a twofold increase in the yield of mature larvae and the lower expenses related to this strategy.

An Action Research to Eliminate Mistakes in Multiplication and Division Operations through Realistic Mathematics Education

In the current study, it is aimed to determine the activities that need to be done to eliminate the mistakes made by primary school fourth grade students in multiplication and division operations and to present solution suggestions for eliminating these mistakes. The study employed action research, one of the qualitative research methods. The study group was constructed by the criterion sampling method, one of the purposive sampling methods. The study group is comprised of 10 fourth graders attending a primary school in the spring term of the 2016-2017 school year in the city of İstanbul and making similar mistakes. A student information form, clinical interview form and student worksheets were used as data collection tools in the study. Activities prepared in line with the principles of Realistic Mathematics Education (RME) were applied in order to eliminate the mistakes made by the students in the multiplication and division operations. When the mistakes made by the students in the multiplication and division operations were examined, it was revealed that the source of the mistakes was the operational, conceptual and problem situations. During the implementation of RME activities, it was determined that the mistakes of the students started to be eliminated. After the implementation, it was found that the mistakes of the students committed in the multiplication and division operations decreased. Thus, it can be said that RME is an effective application in reducing the mistakes in multiplication and division operations made by students in primary school.

Innovative Practice of Foreign Language Teaching in the Post-Pandemic Era: Case of a University in China

COVID-19 has posed a severe challenge to the foreign language teaching as well as the international education management in China. This paper analyzes the key issues exposed in online learning, the unprepared assessment of online course and crisis management of international students taking Shanghai University of International Business and Economics as an example. Both the students and teachers showed a considerable dissatisfaction and their worries about the poor quality and efficiency of online instruction. Other issues raised include teachers’ operation mistakes, ineffective communication and connectivity issues. Students are more likely to cheat in online exams due to the lack of supervision. Different cultural backgrounds, strict prevention and control have increased the difficulty of crisis management of the international student in China. To make better use of online education in the post-epidemic era, suggestions and recommendations are given in online classes and examinations. Also, an efficient crisis management model can be set up for the international students during the post-pandemic era.