Operational Point Of View Research Articles

Comparison of Component-Oriented and System-Oriented Modeling in the Context of Operational Energy System Analysis

Simulation based studies for operational energy system analysis play a significant role in evaluation of various new age technologies and concepts in the energy grid. Various modelling approaches already exist and in this original paper, four models representing these approaches are compared in two real-world hybrid energy system scenarios. The models, namely TransiEnt, µGRiDS, and OpSim (including pandaprosumer and mosaic) are classified into component-oriented or system-oriented approaches as deduced from the literature research. The methodology section describes their differences under standard conditions and the necessary parameterization for the purpose of creating a framework facilitating a closest possible comparison. A novel methodology for scenario generation is also explained. The results help to quantify primary differences in these approaches that are also identified in literature and qualify the influence of the accuracy of the models for application in a system-wide analysis. It is shown that a simplified model may be sufficient for the system-oriented approach especially when the objective is an optimization-based control or planning. However, from a field level operational point of view, the differences in the time series signify the importance of the component-oriented approaches.

Numerical simulation of hydrodynamic performance of taper cascades in transient conditions

The hydrodynamic performance of separation cascades involves determining the distribution of pressure and flow along cascades which are important from the design and operational point of view. In this paper, numerical simulation of hydrodynamic performance of taper cascades in the transient state is presented. This mathematical modeling consisted of a set of hyperbolic partial, ordinary differential and algebraic equations of transient flow in a complex pipe network. In order to achieve this goal, a MATLAB code, named Hydrodynamic Simulation of Separation Cascades (HSSC), has been developed. This code calculates the flow and pressure distribution within the cascade components such as pipes, control valves, tanks and gas centrifuges (GC). Using this code, the results of transient hydrodynamic simulations for a taper cascade with 4 stages and 8 GCs are presented wherein the working gas is xenon, and for different operational conditions, analysis is performed on the equilibrium time and gas holdup.

Towards the applicability of solar nowcasting: A practice on predictive PV power ramp-rate control

Solar forecasting has been widely adopted in modern power system operations to facilitate a reliable and continuous photovoltaic (PV) integration. Solar nowcasting, also known as intra-minute solar forecasting, is a new subdomain of solar forecasting. Nevertheless, despite the significant progress achieved in solar nowcasting over the last decade, one important aspect, that is, applicability—the value and operability of nowcasts in practical grid operations—is generally left out. To that end, this paper brings forth the applicability of solar nowcasting for the first time. Three time parameters involved in operational solar nowcasting are first identified, namely, forecast horizon, forecast resolution, and forecast model updating rate. Then paired with the state-of-the-art PV power ramp-rate control algorithm, i.e., predictive active power curtailment (PAPC), the effect of different time parameters is investigated, thus revealing the nowcasting applicability at large. Through four case studies and eight standardized deterministic and probabilistic solar nowcasting models, the applicability of solar nowcasting on PAPC is shown to be most characterized by the forecast horizon (up to a deviation of ramp smoothing rate around 12%, with smart persistence (SP) being the reference model), and least characterized by the forecast model updating rate (with a deviation of ramp smoothing rate less than 1% for SP). Moreover, the negatively-biased deterministic nowcasts and wider probabilistic nowcasts are found more applicable to PAPC. To promote solar nowcasting applicability on PAPC further, an outlook for future research is provided, from both a solar forecaster's and a system operator's viewpoints.

MASS Level III – Exploration of Current Issues from an Operational Point of View

Despite all efforts to ensure the safety of ships, available statistics show that the human factor remains the biggest problem in the maritime industry. The desire to improve the safety of ships and the related protection of the environment has been at the heart of the Maritime Autonomous Surface Ships (MASS) concept, which is supported by the International Maritime Organisation (IMO). Although the concept itself seems feasible in principle, there are still a number of open questions from an operational point of view. Furthermore, the economic feasibility of the concept is unknown. This paper ad-dresses questions to which there are currently no answers.

Comparison of Extrainsensitive Input Shaping and Swing-Angle-Estimation-Based Slew Control Approaches for a Tower Crane

Tower cranes are needed to move heavy objects safely around construction sites. In tower cranes, payload oscillations are a typical problem that can cause safety issues, especially if the crane is not operated by an experienced user. Depending on the system, there are different causes for oscillations, e.g., inertial forces from the crane movement or external forces, such as weather conditions. Hence, the selected control law for input tracking plays an important role to limit the oscillatory motion and to help the crane operator to prevent unwanted operations. In this paper, we study the slew control of a tower crane application from the viewpoint of reducing payload oscillations. Two different approaches are studied: open-loop control based on extrainsensitive input shaping and closed-loop swing angle control, based on the estimation of the hoist cable angle. The proposed control approaches are validated by running the developed control program against a multibody mechanics simulator containing a model of a Liebherr tower crane. The studied control laws are also evaluated using an experimental setup, which consists of a two-axis manipulator, inverters, and a programmable logic controller in which the studied control methods are implemented. The results from the multibody dynamics simulations and from the experimental setup are presented and evaluated from the viewpoint of crane operation.

Cybersecurity risk assessment subjects in information flows

A modern society includes several critical infrastructures in which digitalization can have positive impacts on the levels of autonomy and efficiency in the use of infrastructure systems. Maritime transportation is an example of an infrastructure that currently needs development in the digitalization of its operations and processes. At the same time, maritime processes represent a large-scale cyber environment, thus trustable information distribution between system elements of the processes is needed. Since 2020, the Sea4Value / Fairway (S4VF) research program in Finland has been working to develop maritime digitalization which can lead to autonomy processes in the future. The first stage of the program has led to a demonstration phase of remote fairway piloting. This remote fairway piloting process, “ePilotage,” is a complex system-of-systems entity. In this entity, fairway systems, ship systems and control center systems are the main processes from the operational point of view. Remote pilotage operations need support processes such as vessel traffic service (VTS) and weather forecast services. Situation awareness from other vessels and the stakeholder’s processes are also essential information for the entire piloting operation. In this context, a new concept of information flows at the technical level will be based partly on cloud servers. In this paper, a cybersecurity risk assessment has been carried out at the technical level of information and communication technologies (ICT), and it concerns information transmission between a ship and a cloud server. It describes the most important topics for a comprehensive risk assessment in a specific ship-to-cloud information flow of the fairway process. The findings of the study can be considered good examples of the management of cybersecurity risks in critical information flows between all main system blocks of the fairway process. The research question is as follows: “How can the cybersecurity risks of information flows in a system-of-systems entity be described and evaluated?” The main findings are related to the risks of transmitting information from a ship to a cloud server. The methodology that has been used is based on analyzing the probabilities of cyberattacks occurring in relation to the probabilities to defend against these actions. The main risk assessment topics have been listed.

Enterprise Risk Management and Company’s Performance

The purpose of this study is to investigate the relationship between enterprise risk management (ERM) and company performance in the Chinese commercial industry. An enterprise risk management index was constructed from a strategic and operational point of view to assess the ERM level of Chinese commercial companies. ERM is also known as an integrated, comprehensive, and strategic management using the Simona-lulia (2014) approach. The study used a sample of 175 listed Chinese commercial companies from 2009 to 2018, and found that the imperfect ERM in the Chinese commercial industry as a whole had a negative effect on the performance of the companies. It also found that the size of the company, financial leverage, and intellectual capital can influence enterprise risk management. These results established a strong link between enterprise risk management and company performance in the Chinese commercial industry.

A definition of the asymptotic phase for quantum nonlinear oscillators from the Koopman operator viewpoint.

We propose a definition of the asymptotic phase for quantum nonlinear oscillators from the viewpoint of the Koopman operator theory. The asymptotic phase is a fundamental quantity for the analysis of classical limit-cycle oscillators, but it has not been defined explicitly for quantum nonlinear oscillators. In this study, we define the asymptotic phase for quantum oscillatory systems by using the eigenoperator of the backward Liouville operator associated with the fundamental oscillation frequency. By using the quantum van der Pol oscillator with a Kerr effect as an example, we illustrate that the proposed asymptotic phase appropriately yields isochronous phase values in both semiclassical and strong quantum regimes.

Numerical simulation of a precision air conditioner under variable working conditions

Artificial intelligence (AI)-based intelligent working parameter setting of cooling equipment is a promising strategy for energy savings in large data centers. For this purpose, the performance curves of each piece of equipment must be obtained under variable working conditions. In the present study, a porous media computational fluid dynamics (CFD) model was established to investigate the flow and thermal performance of a finned-tube heat exchanger in a precision air conditioner (PAC) of a large data center with 3000 server racks. The temperature and velocity at the air outlet of the PAC were measured at 15 measurement points, and the results agreed well with the simulation results with a difference less than 10%. Under various inlet temperatures and flow rates of both chilled water and air, the heat transfer rate and pressure drop were studied. From the viewpoint of economical operation of the PAC, a critical flow rate was revealed for water and air, respectively. In addition, empirical formulas of the heat transfer rate of the PAC were obtained, which can facilitate energy savings by determining the optimized temperature of the chilled water and operating parameters of the pump and fan.

Can hyperloops substitute high speed rails in the future?

While the existing literature has focused on the impact of High Speed Rails (HSR) on the airline industry, we believe that this research is the first to examine the substitutability of HSR with Hyperloop services from an operational point of view. A simulation model is developed to compare the performance of both these alternate transportation modes for a network of three major cities in Europe (Amsterdam, Paris, and Frankfurt). Our results indicate that with a significantly lower pod capacity, the Hyperloop system will still be able to serve more customers compared to the HSR services, while the vehicle utilization is observed to be higher in the latter alternative for a given period of time. In addition, sensitivity analysis is conducted to assess the impact of variation in capsule capacity, number of pods in the system, and commuter variability. We further compare the two transportation modes with respect to their estimated infrastructure and operational costs as well as CO2 emission. Finally, a cost–benefit analysis is conducted to evaluate the passenger ticket price for Hyperloop services.

Improving patients’ experience concerning insufficient informational flow to patients during COVID-19 pandemic: Case study of a traditional Chinese medicine clinic

ABSTRACT Objective To improve patients’ experience concerning insufficient informational flow to patients waiting at the dispensary station – case study of a traditional Chinese medicine clinic. Method The service system was explored via qualitative techniques such as interviews and constructing the customer journey map. Then, experience and operational issues were defined through experience ratings at each touchpoint, patient interviews, and root cause analysis. The solution was identified via brainstorming and prototyping. A prescription tracking system was proposed with a finish time estimation algorithm. Results The overall satisfaction score at the dispensary station, comparing before-after system implementation in 2019, was increased 37% from the average score of 3.27 to 4.47 using 5-point Likert scales. The mean absolute percentage error (MAPE) of the waiting time estimation model that included the buffer time (upper bound at 95%) is 52%. Conclusion This methodology, which included both patient experience and operational improvement viewpoints, could successfully improve both the patient experience and the related operation system at its critical touchpoints. Moreover, the data from the prescription tracking system could be used to estimate the number of patients waiting in the system, allowing the clinic to better manage its waiting space and capacity during the COVID-19 pandemic.

DẠY HỌC KHÁI NIỆM TOÁN HỌC Ở TRƯỜNG TRUNG HỌC PHỔ THÔNG NƯỚC CỘNG HÒA DÂN CHỦ NHÂN DÂN LÀO THEO QUAN ĐIỂM HOẠT ĐỘNG

The article builds a process of teaching the concept of equations and inequalities from an operational point of view to develop the ability to learn Mathematics for high school students in Lao PDR. On the basis of inheriting and applying Vietnamese theories, this article has proposed the process, core activities, and component activities in teaching Mathematics concepts in high schools of the Lao People's Democratic Republic. The article presents an illustrative example of teaching equations according to the Math program of Lao PDR

Fabrication of a Stainless-Steel Pump Impeller by Integrated 3D Sand Printing and Casting: Mechanical Characterization and Performance Study in a Chemical Plant

The emergence of additive manufacturing is renovating the landscape of available production technologies. In this paper, we describe the fabrication of a closed vane pump impeller (ϕ 206 mm, height 68 mm, weight 4 kg) by binder jetting 3D printing of a sand mould followed by casting using stainless steel 316 to create an identical copy of a part in service in a chemical plant in Tarragona, Spain. The original part was reverse engineered and used to create a sand mould by binder jetting 3D printing on which new impellers were fabricated by casting. Metallographic studies showed an austenitic matrix with 6.3% of ferritic phase and 40 μm × 8 μm ferrite grains without precipitated carbides. The impeller was put into operation in a centrifugal pump at a polyol/polyglycol plant belonging to Dow Chemical Ibérica SL from October 2020 to April 2021. Process variables related to the pump behaviour were compared with the same variables obtained in previous cycles with the original impeller for three different product viscosities (30, 180, and 500 cSt). At 500 cSt, the average current consumption was 9.34 A as compared with the 9.41 A measured with the original impeller. Similarly, the pump pressure remained essentially constant during process operation with both impellers (3.97 bar with the new impeller vs. 3.99 bar with the old). Other monitored parameters (product flow, tank level) were similar in both cases, validating the fabrication strategy from an operational point of view. This work further demonstrated that the implementation of additive manufacturing technologies in chemical process engineering is a useful solution to fabricate spare parts that are difficult to replicate with other technologies, providing consequent economic benefits.

Modeling and Optimization of the Bubble Detachment Diameter for a Pool Boiling System

AbstractPrediction of boiling heat transfer for pool boiling systems is crucial from the viewpoint of safe operation as well as in terms of logical use of energy. Here, five pool boiling processes for calculating the bubble detachment diameters are described. The effects of liquid density and vapor density on the bubble detachment diameter of these pool boiling systems, namely, ethanol, methanol, water, Na2SO4‐water, and NaCl‐water, are determined by applying response surface methodology. According to P‐values and analysis of variance, there is a good agreement between the obtained regression models for the five pool boiling processes and experimental data for estimation of the bubble detachment diameters.

Digital Innovation and Migrants’ Integration: Notes on EU Institutional and Legal Perspectives and Criticalities

These notes describe the evolution of the EU strategy for the integration of Third Country Nationals since the Tampere Program in 1999 until the second Action Program (2021–2027). It highlights the EU’s endeavor to close the gap between migrants and EU citizens in compliance with the EU general anti-discrimination policy and, since the entry of the Lisbon Treaty into force, of the EU Charter of Fundamental Rights. Accordingly, the current integration strategy has a much wider legal and financial basis than the one described by art. 79.2 of the TFEU. This new individual-centered and wide-ranging public approach can now be strengthened through the new European Digital Agenda, whose aim is also to reframe and make the relations between the individual and public administration more user friendly. However, in the human mobility domain, the large EU acquis, which is currently focused on internal security, should be re-balanced from a legislative and operational point of view to avoid the risk of infringing on data protection principles and establishing a mass surveillance framework, which could be incompatible with the EU as a democratic society and a rule of law-abiding organization. Within this very complex framework, a promising development is the establishment of a new European Asylum Agency, which may pave the way for more consistent EU asylum and migration policies.

What could a central bank digital currency look like in the euro area? The outcome of a hackathon exercise

Central bank digital currency (CBDC) has become a widely discussed subject in central banking. Most of the literature, however, has been theoretical, and there exists no precise description of what a CBDC could look like in a major economy. The Bank of Finland conducted an internal hackathon exercise to shed more light on the practical questions of a CBDC. This paper presents the findings of that exercise. It is a model of a CBDC for the eurozone, and it attempts to approach the question from an operational point of view. The model is not a suggestion, and it probably omits many important considerations. However, by presenting one possible description of a CBDC, it contributes to the policy discussion and provides a practical reference that exemplifies the degree of complexity that central banks will be facing when considering the issuance of a CBDC.

Effect of the addition of organic wastes (cork powder, nut shell, coffee grounds and paper sludge) in clays to obtain expanded lightweight aggregates

Four organic solid wastes (coffee grounds, ground nut shell, paper money sewage sludge and cork powder) have been investigated as bloating inducing agents in lightweight aggregate (LWA) manufacturing when mixed in small proportions (2.5wt.%) with three types of clays. The pellets obtained were fired in a rotary kiln at the maximum feasible temperature for 4min. A similar impact was observed both in the working conditions and in the properties of the LWAs, showing that the differences between said residues are not as decisive as those of the clays to which they are added. The organic wastes have played a crucial role in achieving reducing conditions inside the aggregate. Thus, their addition has led to substantial improvements both from an operational point of view, lowering the working temperature, and from a technological perspective, favoring bloating and the development of a highly porous and lightweight structure. Leachate studies have shown that the LWAs meet the regulatory limits. The outcomes of this investigation show that, in line with the precepts of the Circular Economy, the recovery of organic wastes of different nature can have a place in the production of environmentally friendly LWAs.

Operational Detection of Entanglement via Quantum Designs

AbstractFrom an operational point of view, several new entanglement detection criteria are proposed using quantum designs. These criteria are constructed by considering the correlations defined with quantum designs. Counter‐intuitively, the criteria with more settings are exactly equivalent to the corresponding ones with the minimal number of settings, namely the symmetric informationally complete positive operator‐valued measures (SIC POVMs). Fundamentally, this observation highlights the potentially unique role played by SIC POVMs in quantum information processing. Experimentally, this provides the minimal number of settings that one should choose for detecting entanglement. Furthermore, it is found that nonlinear criteria are not always better than linear ones for the task of entanglement detection.

Design and Fabrication of a Magnetic Actuator for Torque and Force Control Estimated by the ANN/SA Algorithm.

Magnetic manipulation has the potential to recast the medical field both from an operational and drug delivery point of view as it can provide wireless controlled navigation over surgical devices and drug containers inside a human body. The presented system in this research implements a unique eight-coil configuration, where each coil is designed based on the characterization of the working space, generated force on a milliscale robot, and Fabry factor. A cylindrical iron-core coil with inner and outer diameters and length of 20.5, 66, and 124 mm is the optimized coil. Traditionally, FEM results are adopted from simulation and implemented into the motion logic; however, simulated values are associated with errors; 17% in this study. Instead of regularizing FEM results, for the first time, artificial intelligence has been used to approximate the actual values for manipulation purposes. Regression models for Artificial Neural Network (ANN) and a hybrid method called Artificial Neural Network with Simulated Annealing (ANN/SA) have been created. ANN/SA has shown outstanding performance with an average R2, and a root mean square error of 0.9871 and 0.0153, respectively. Implementation of the regression model into the manipulation logic has provided a motion with 13 μm of accuracy.

Wheelchair driving strategies: A comparison between standard joystick and gaze-based control

ABSTRACT This paper aims to evaluate and compare the driving performances achieved with a power wheelchair using a standard joystick versus a novel gaze-based technology. The gaze-based interface, called RoboEYE, involves a novel paradigm of computer interaction that handles the receipt of information from an eye tracker, using it as a continuous input for wheelchair navigation. A pool of 36 subjects has tested both technologies in a circuit designed considering the Wheelchair Skill Test. The experimental analysis involved evaluations of specific metrics of motion and the submission of questionnaires to collect required information about perceived feelings and mental workload. The joystick proved to be the best driving interface. It turned out to be more accurate and efficient than the gaze-based solution. However, the latter achieved only small differences in driving kinematics. These differences can be considered negligible from an operational point of view, offering a driving experience similar to that achievable with the joystick. Testers reported no particular stress, fatigue, or frustration when switching from one interface to another. These elements suggest that the proposed gaze-based solution is an appropriate alternative for a technology transition driven by a pathological change in the user’s condition.