Technical System Research Articles

Green total factor productivity of dairy cows in China: essential facts from the perspective of regional heterogeneity

Introduction: Enhancing the green total factor productivity of dairy cows (GPDC) is crucial for fostering the low-carbon sustainable development of the dairy industry.Methods: This research utilizes the Minimum distance to weak efficient frontier–Meta frontier–Malmquist–Luenberger (MinDW-MML) index to examine the GPDC using the unbalanced panel data on dairy cows in 26 provinces of China from 2004 to 2020, taking into account regional heterogeneity and unexpected output.Results: The findings revealed that 1) from 2004 to 2020, China’s GPDC displayed a fluctuating and declining trend, with the steepest decrease occurring from 2007 to 2010 (2.26% at the common frontier and 1.81% at the group frontier). The fundamental cause of the low GPDC, as seen from the standpoint of efficiency decomposition, is technical advancement (technological change, or TC); 2) the GPDC exhibits a declining trend from east to west to central China for the two-level frontier. The eastern region benefits clearly from technological advancement (TC) and improved technical performance (EC), while the middle and western regions are mostly constrained by TC; and 3) the GPDC displayed regional heterogeneity at several scales. Although the efficiency values of medium- and small-scale aquaculture were low and large-scale aquaculture GPDC in the eastern and western regions was greater than 1, the GPDC did not reach the effective state in the central region.Discussion: Based on these findings, we propose policy recommendations such as promoting technological innovation and low-carbon technology in dairy farming, improving the technical system of dairy farming, and optimizing the industrial layout of dairy farming, which will serve as a model for future high-quality and sustainable dairy farming development in China, and provide an experience for green dairy farming development in other countries.

Design of Image Processing Technology Support System in Human-Computer Collaborative Visual Design Assisted by Artificial Intelligence Technology

Aiming at the problems of high cleaning intensity, low efficiency, and hidden safety hazards of high-altitude curtain walls, this study proposes that the image processing method is a kind of image processing technology in human-computer collaborative visual design. The algorithm uses generalized mapping to scramble the picture and then expands and replaces the scrambled pictures one by one through the image processing technical support system. Studies have shown that this calculation method has mixed pixel values, good diffusion performance, and strong resistance performance. The pixel distribution of the processed image is relatively random, and the features of similar loudness are not relevant. It is proved through experiments that the above calculation methods have strong safety performance.

Exploring the appropriate technology for green renovation of rural buildings incorporating regional culture: Taking the renovation of village houses in Conghua, Nanping, Guangzhou as an example

In view of the rising energy consumption of rural buildings in recent years and the neglect of the connection with regional architectural culture in the construction process, this study explains the connotation and representation of regional culture based on the theoretical tool of cultural regional character, and constructs a suitable technical system for green transformation of rural buildings incorporating regional culture from five aspects, which are regional character creation, outdoor environment improvement, envelope structure performance optimization, indoor environment quality improvement, and renewable energy utilization. Based on the construction of this system, this study takes the renovation of the village residence in Nanping, Conghua, Guangzhou as an example, and explores the ways to achieve green and sustainable development in the renovation of rural buildings in the Lingnan Guangfu area with the guidance of the system and method of integrating regional culture and modern green building technology. The study compares the buildings of Nanping village residence in Conghua, Guangzhou, before and after the renovation, and finds that after the renovation, the building consumes less energy, the spatial quality is improved, and the overall spatial and stylistic expression is more in line with the regional cultural characteristics, which provides theoretical and practical references for the green renovation of rural buildings.

Ancestral Integrated Water Management Systems as Adaptation Tools for Climate Change: The “Acequias De Careo” and Historical Water Management of the Mecina River in Sierra Nevada (Granada, Spain)

ABSTRACT Historical water management systems, in operation since the Islamic period (eighth to fifteenth centuries), have generated important irrigated areas and transformed the landscapes in a co-evolutionary process over more than a thousand years. In the Sierra Nevada, the so-called acequias de careo stand out as a singular technical system for water recharge from the thaw. This way of managing surface- and groundwater, as well as soil and vegetation, while generating social, economic, and environmental benefits, is an example of Integrated Water Management and Nature-based Solutions. This system has proven its efficiency and resilience, having been operational since the Middle Ages. The abandonment of these water management systems is an irreparable cultural and environmental loss. The transdisciplinarity of this case study can be considered a success and a good example for its application in other geographical and cultural contexts promoting sustainable and resilience solutions based on historical socio-ecological systems and local ecological knowledge and practices.

A Design of a Miniaturized Receiver Front-end of an X-band Radar

Based on the development and practice of a high-frequency carrier-based aircraft radar receiver front-end, a design of a high-density miniaturized X-band receiver front-end with its environmental adaptability is introduced. The system scheme introduces the key technologies of technical scheme, specifications allocation, circuit realization and test system design. The front-end of the designed receiver has the characteristics of small volume, high density and good maintainability. The practice shows that the environmental adaptability and test features of the receiver meet the requirements of carrier-based aircraft radar.

Advances in extraction and purification of citrus flavonoids

AbstractFlavonoids are the representative active substances of citrus with various biological activities and high nutritional value. In order to evaluate and utilize citrus flavonoids, isolation and purification are necessary steps. This manuscript reviewed the research advances in the extraction and purification of citrus flavonoids. The structure classification, the plant and nutritional functions, and the biosynthesis of citrus flavonoids were summarized. The characteristics of citrus flavonoids and the selection of separation strategies were explained. The technical system of extraction and purification of citrus flavonoids was systematically described. Finally, outlook and research directions were proposed.

Theory and Practice of Hydrodynamic Reconstruction in Plain River Networks

The river networks in the plains of China are in low-lying terrain with mild bed slopes and weak hydrodynamics conditions. Filled with intense human activities, these areas are characterized by serious water security problems, e.g., frequent floods, poor water self-purification capabilities, and fragile water ecosystems. In this paper, it’s found that all these problems are related to hydrodynamics, and the spatiotemporal imbalance of river network hydrodynamics is identified as the common cause of these water-related problems. From this, a theory for the hydrodynamic reconstruction of plain river networks is proposed. In addition to the importance of the flow volume, this theory highlights the role of hydrodynamics and limited energy in improving the ecological water environment. The layout of water conservancy project systems (e.g., sluices and pumping stations) is optimized to fully tapping the potential integrative benefit of projects. The optimal temporal and spatial distributions of hydrodynamic patterns is reconstructed in order to meet the needs of the integrated management of complex water-related problems in river networks. On this basis, a complete theoretical method and technical system for multiscale hydrodynamic reconstruction and multi-objective hydraulic regulation in plain river networks with weak hydrodynamics is established. The principles of the integrated management of water problems in river network areas are put forward. The practical application and efficacy of the theory are demonstrated through a case study aiming to improve the water quality of the river network in the main urban area of Yangzhou City.

Managing students’ attitude, learning engagement, and stickiness towards e-learning post-COVID-19 in Australian universities: a perceived qualities perspective

ABSTRACT Studies have been conducted on university students’ acceptance of e-learning systems during COVID-19. However, less attention has been paid to students’ use of e-learning post-pandemic. This research provides a more comprehensive framework to investigate the effects of e-learning students’ various quality perceptions on attitude, learning engagement, and stickiness toward e-learning platforms. A survey-based quantitative method is adopted by this study in which sample data are collected from students in Australian universities. A total of 403 valid samples were analysed using covariance-based structural equation modelling. This study found that students’ perceived educational quality, service quality, information quality, and technical system quality play different roles in their attitudes and behaviours towards e-learning. It expands the information system success model by comparing the effects of students’ various perceived qualities on their ongoing commitment to e-learning. It provides insights to e-learning providers in pursuing better designs and more sustainable development of educational information systems.

Simulation modeling of the lifting and assembly module of the supports of the structural coating

The materials of the article are devoted to the issue of simulation modeling of construction mechanized technological equipment, in particular, modeling of the lifting and assembly module for the installation of a structural coating. Today, an urgent task in the construction market is the construction of large-scale structures, the life cycle of which is shortened, but the construction terms are reduced. Such a need exists in the construction of shelter hangars, field hospitals, warehouses, etc. As a rule, for urgent needs, buildings with light construction structures are erected, the covering of which is formed by structural blocks. A feature of such structures is multi-element support elements. A lifting assembly module is proposed for the installation of such structures.
 It is essential that the mounted structural coating is assembled on the heads of the lifting and collecting modules in blocks, and the lifting of the structural block to the design mark occurs thanks to the module while simultaneously raising/assembling the supporting elements of the coating. Simulation computer modeling tools were used to study the possibility of implementing the assembly process using the lifting assembly module. It is proposed to use the parametric formation of sketches and 3D models when forming the design features of the module. The dissection of the elements of the new assembly module, support elements and structural coating to the level of simple parts made it possible to determine their mass characteristics with sufficient accuracy. The basic technical indicators of the assembly module and building structures, which can be used in the development of the assembly technology, were obtained.
 Approaches to the use of cloud databases when using unified elements during design are defined.The use of simulated geometric modeling data allows to analyze the strength properties of the components of the technical system and, together with the visual observation data, to create a common information model of the building object with the possibility of qualitative analysis of the indicators of the specified elements of building structures.

On the phase transition of [formula omitted]-out-of-[formula omitted] systems with applications to optimal maintenance

An effective method for improving the reliability of a technical system is to build redundancy into it. A commonly used redundancy structure in reliability engineering is the k-out-of-n structure. A k-out-of-n structure, consisting of n components, operates if and only if at least k components operate. This paper studies a high-dimension feature of k-out-of-n systems consisting of independent and identical components. This phenomenon, commonly known as a phase transition in high-dimensional probability, shows that in a system consisting of a large number of components, if the components operate independently with common reliability, then the system reliability undergoes a ‘sharp transition’. That is, in a narrow interval, the value of the system reliability rapidly declines. We first consider the systems whose components have common static reliability p∈(0,1). Then we focus on k-out-of-n systems with time-dependent reliability. As an application of the results, we employ the phase transition property to propose optimal age-based maintenance for the system.

Intellectualization of search for the causes of failure of components of a complex technical system

Intellectualization of search for the causes of failure of components of a complex technical system

Implications of the positive risk balance on the development of automated driving

Objectives Automated driving (AD) from SAE level 3 onwards represents a paradigm change from human driver controlling the vehicle to a technical system controlling it. In this light, different regulatory bodies (European Commission, Germany, etc.) have defined guidelines for the operation of such a system. One core principle of these guidelines is that the automated operation needs to be at least as safe as human driving—often referred to as the “positive risk balance.” However, these guidelines are general and do not provide details on what this means in a practical sense. This article discusses a method to demonstrate how positive risk balance can be addressed in practice. Methods Starting from a detailed analysis of corresponding guidelines and a literature review of possible risk assessment frameworks, a comprehensive approach has been developed to consider ethical requirements for the development of AD. This approach covers different development stages. The PrOACT-URL (Problems, Objectives, Alternatives, Consequences, Trade-offs, Uncertainty, Risk attitudes, and Linked decisions) approach was chosen for reporting of the work. Results The article will present the approach developed by BMW to ensure that a positive risk balance is achieved for an AD system. The approach is presented per development stage (concept phase, AD development phase, verification and validation phase, post–start of production phase). In the concept phase, the scope is to define how good a human driver is and how good an AD needs to be. In the AD development phase, first the relevant system requirements need to be derived. Monte Carlo experiments in combination with Bayesian networks are applied. The fulfillment of these requirements is checked in the verification phase through simulations and test track and real-world tests. For validation of the risk balance, the impact of AD in terms of traffic safety is derived by means of simulation. In the post–start of production phase, field observation is used. Conclusion The safety of AD is paramount when it comes to its operation and ensuring trust in this technology. The described approach contributes directly to building this trust by considering the principle of a positive risk balance throughout the development in addition to existing safety standards for advance driver assistance systems, such as ISO 26262, ISO21434 or ISO 21488.

Towards Hierarchical Workflows in SysML to Support Virtual Validation of Technical Systems

Innovative Model-Based Systems Engineering (MBSE) applies function-oriented hierarchical system architecture and utilizes Systems Modeling Language (SysML) for virtual testing. However, for complex systems, the relevant virtual tests are scattered at different hierarchy levels. Manually performing these virtual tests requires a lot of effort and leads to the potential risk of errors due to the overlooking of some tests and functions. In order to solve these problems, it is necessary to develop automated virtual validation workflows for the function-oriented system architecture. This contribution proposes a standardized virtual validation workflow design framework corresponding to the hierarchical functional architecture to organize virtual tests. The virtual tests are also modeled in workflows consisting of a set of simulation activities that can execute domain models to simulate system behaviors. The simulation activities are developed modularly, corresponding to the classification of the domain models. The resulting workflows are implemented in a wind turbine (WT) system. It demonstrates that the workflows enable automated validation at all hierarchy levels and early detection of technical system failure risks. The design framework allows for the synchronous creation of validation workflows as functions are added or decomposed. The standardized design ensures easy redesign and function reuse across different systems. Modular design, based on model classification, enhances design agility and adaptability in various system contexts. The proposed virtual testing workflows automatically execute corresponding simulation activities sequentially.

TECHTASK: A technical support system of Northwestern University

TECHTASK: A technical support system of Northwestern University

Validation of Reliability Indices during Experimental Development of a Complex Technical Series System

Introduction. The article studies the problem of validating the specified levels of reliability during experimental development of a complex technical series system. Such tasks arise when it is required to make a decision on testing the system as part of a larger one or on the completion of experimental development and the start of series production. The study is aimed at validating the reduction of the experimental development time. The task is to determine whether the hypothesis Но is accepted or rejected.Materials and Methods. To implement the research objective and task, a critical area described by the inequality was constructed based on the test results. The formulation of the requirements validation task was based on well-known approaches to testing statistical hypotheses. The conceptual apparatus of information theory, probability, and statistics was involved. The theoretical and applied literature on mathematical methods in reliability theory was studied. The particular tasks of the work were solved by known ways. Thus, the probability of obtaining the exact number of successful outcomes in a certain number of experiments was determined by the Bernoulli scheme. The exact confidence interval based on the binomial distribution was derived from the Clopper-Pearson relation. The theorem of A.D. Solovyov and R. A. Mirny made it possible to assess the system reliability based on the test results of its components.Results. Control rules adequate to the stage of experimental development (with insufficient data on the technical system) and the stage of series production were mathematically defined. The probability of a successful outcome when testing technical systems was represented by:– the probability of event for a system element;– confidence value;– required scope of tests.In these terms, the null and alternative hypotheses and the corresponding reliability control procedures were investigated. Two provisions were considered. The first one provided using the null confidence hypothesis Но = {Р ≥ РТ} and an alternative Н = { Р < РТ} to confirm the requirements (РТ, γ) for the reliability indicator of one parameter for any (РТ, γ). In this case, one trouble-free test was enough. The second provision considered a sequential technical system with independent elements that were tested separately from the system according to the Bernoulli scheme for one parameter. We considered the requirements for the system in the form of a set of values (РТ, γ) and the requirements for any of its elements (РТi, γ). They coincided when the planned outcome of the tests corresponded to the cases when the ratio Р= lim 1≤i≤N : Р i = Р m was fulfilled, and the null alternative hypothesis was selected from the theory of statistical hypothesis testing.Discussion and Conclusions. The experimental development strategy should be implemented in two stages: the search and validation of the reliability of the elements through a series of fail-safe tests. In this case, the planned scope of tests of each element is determined taking into account the confidence probability, the lower limit of the confidence interval, and the requirements for reliability indices of one parameter of the technical system. If the use of the null confidence hypothesis is acceptable, one fail-safe test is sufficient to confirm the requirements for the reliability index.

DYNAMIC LOADS IN ELASNIC ELEMENTS/ROPES OF CONSTRUCTION CRANES ANALYSIS AND OPTIMIZATION

In the study, an analysis of the dynamic model of construction cranes’ load lifting mechanism, proposed by professor Loveikyn V.S. and others, was carried out. In order to determine the dynamic loads in the elastic rope, a dynamic model is used, in which all sections of the shafts are considered rigid, and only the cable is elastic. Bringing the engine rotor masses, brake pulley, gears, drum and load to the rope branchers that are wound on the drum, allows the original complex multi-mass tech-nical system to be reduced to a simplified (two-mass) crane lifting mechanism dynamic model, which is comprehensively and in detail analyzed in transition-type modes (for example, in the start-up mode). 
 An established and substantiated criterion for the movement quality of the hoisting crane load mechanism, at which rope system dynamic stresses are minimized in the starting mode, as well as the dynamic coefficient for different ways of lifting the load: 1) “from the weight”; 2) “with a pick up”/ “from the base” − typical during cranes real work in cargo lifting/lowering operations (loading and unloading). 
 Classical variational calculus methods usage (Euler-Poisson equation) allows to determine the conditions, according to which the above-mentioned criterion for the movement quality of the load lifting mechanism can be implemented.
 The movements laws of the load cargo and the drive crane mechanism are also defined, as well as law of dynamic coefficient change in time, for which there is no oscillation nature of time dependence, and the specified time functions have a mono-tonically growing character over time.
 The results obtained in the work allow (when using mechatronic control systems for the cargo lifting process) prevent overloading of the crane rope system and possible emergency situations, which lead to breaks in the elastic elements of the load lifting mechanisms (i.e. ropes), and also clarify and improve the existing engineering methods of similar complex technical systems calculations in their real operation modes.

Challenges facing students in Using Learning Management System (LMS) in the face of COVID-19 in the Faculty of Business Studies at Takoradi Technical University

Learning Management System (LMS) has been an effective medium for most schools, colleges and universities to engage students and disseminate instructional materials during this coronavirus pandemic. Notwithstanding, students who have experienced the LMS platform in their learning express concerns which appear to outweigh the positives of the system. Hence, this study was conducted to explore the challenges students face in the use of the LMS in the faculty of Business Studies at the Takoradi Technical University. Cross-sectional survey design was employed with a sample size of 200 business studies. Questionnaire was used for the data collection and both descriptive and inferential statistics were employed in analyzing the data. The study found that students were not trained and equipped with the requisite knowledge and skills to use the LMS before its introduction. In addition, there were no technical and student support system to guide the students to learn through the LMS. Also, high cost of internet data, slow internet and Wi-Fi connectivity in the University were some of internet challenges which has resulted in student being demotivated and sees the LMS as not effective system for learning in the university. It is recommended that the university management to organize a training to equip the students with the needed knowledge, skills and understanding to effectively use the LMS. Also, the university management should partner with the telecommunication networks such as MTN, Vodaphone etc. to provide affordable data for students to access the LMS

Energy Saving Transmission Line Evaluation Based on Mechanical and Electrical Characteristics Analysis

In order to improve the safety and reliability of transmission lines in certain areas, an energy-saving line selection scheme based on mechanical and electrical characteristics analysis is proposed. We determine the structural technical parameters and system conditions of the new energy-saving conductor through specific cases. In the mechanical characteristics, the dynamic stress, safety factor and the maximum sag of four different types of conductors during galloping are compared; In electrical characteristics, the current carrying capacity and resistance loss are mainly calculated. Finally, the economic and social benefits of energy-saving conductor are analyzed in combination with the specific project situation, and the specific precautions in the conductor selection process are analyzed, which provides a technical reference for the design, selection and application of energy-saving conductor.

Monitoring and forecasting the condition of structures in the small river basins in southern Russia

Introduction. The southern regions of Russia need to adapt to higher peak river flows and flash floods. Since 1960, the number of recorded flood events has increased. The intensity and severity of flood events tend to decrease, but their annual frequency is increasing. This illustrates the social component of flooding. Trends in the number of flood events are closely related to the increasing population in river valleys. “Integrated management” of construction sites in river basins is based on three elements: monitoring, forecasting and early warning, vulnerability assessment, mitigation and response. The purpose of this study is to establish means of prediction, risk assessment of operational construction projects in river basins taking into account the current natural and climatic factors.
 
 Materials and methods. The research is based on the factual material collected in the field studies in the river basins of recreational regions of southern Russia. Design, construction and operational documentation of complex structures was analyzed and their structural elements were evaluated.
 
 Results. On the basis of the carried out theoretical, field and numerical researches, the problem of increasing ecological safety of the urban environment was solved by monitoring, assessing, ranging of the technical condition of building structures and forecasting risks in the urbanized areas of river basins. The results of the research should be considered as a basis of practical methods for the complex estimation of ecological safety of natural and technical system of river basins. Further development of the topic can be connected with the scaling studies of urbanized territories, monitoring crisis sites and forecasting of the further condition of construction projects by subjects.
 
 Conclusions. The developed software package has practical importance, the product is implemented in the Republic of Crimea, in the operation of the long-term operated HES complexes of the Partizanskoe reservoir supplying water to the city of federal importance Simferopol and the Alminsky reservoir irrigating Bakhchisaray region of the peninsula and it is also being tested in the Krasnodar Territory, the Republic of Dagestan, the Stavropol Territory and Caucasian Mineral Waters.

Modes of psycho-informational interaction of a human operator with technical, information and intellectual systems

A decrease in the attention of the operator or his incorrect reaction during prolonged interaction with the technical system is one of the most serious problems. From the point of view of the theory of information metabolism of the psyche - socionics - this means that the human psyche does not receive adequate information signals that support its necessary working state, concentration of consciousness, level of attention, etc. The solution to this problem is connected with the definition of the information characteristics of the technical system and with the construction of adequate information interaction in the integral complex “operator - technical system”. It is achieved by using the method of socionical analysis and modeling. Knowledge the information structure of a technical system gives opportunity to predict a number of features of its behavior. It gives additional significant information about the parameters that must be taken into account for adequate monitoring of the system's behavior. The second task is related to the form of providing the system with signals to the operator for the subsequent adequate reaction. A human operator has a certain type of information metabolism, and receiving information on some informational aspects is familiar and convenient for him, but on the other is associated with tension. To solve this problem there are identified and considered 16 possible specific modes of psycho-informational interaction of a human operator as a carrier of a certain socionic type of information metabolism with technical or electronic systems, including artificial intelligence systems. These modes can be complementary, resonant, neutral or non-complementary. The specificity of psycho-informational interaction is certainly important from the point of view of efficiency and safety.