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Abstract

The article presents a brief exposition of alternative ways of creating virtual objects and the status of their existence inspired by the relevant views of Plato, Aristotle, Franz Brentano and Karl Popper as well as various conceptions of representation. I argue that the present state of research on the problem of “computer” virtuality shows that it is necessary to explore first the ontological issues of virtual objects. Only these issues will solve the mystery of the creation and existence of virtual objects. The consideration of these issues are suppressed by the fact that contemporary philosophy has removed both metaphysics and, with-it, ontology. That is why, and for reasons for reasons of substantive accuracy, I show how traditional ontological and ontologically inspiring approaches are—when modified— promising candidates for exploring the nature of virtual objects, first of all, problems of their existence and creation.

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Authors and Affiliations

Mariusz Mazurek
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Abstract

Current networks are designed for peak loads leading to low utilization of power resources. In order to solve this problem, a heuristic energy-saving virtual network embedding algorithm based on the Katz centrality (Katz-VNE) is proposed. For solving an energy-saving virtual network embedding problem, we introduce the Katz centrality to represent the node influence. In order to minimize the energy consumption of the substrate network, the energy-saving virtual network embedding problem is formulated as an integer linear program, and the Katz-VNE is used to solve this problem. The Katz-VNE tries to embed the virtual nodes onto the substrate nodes with high Katz centrality, which is effective, and uses the shortest paths offering the best factor of bandwidths to avoid the hot nodes. The simulation results demonstrate that the long-term average energy consumption of the substrate network is reduced significantly, and the long-term revenue/cost ratio, the acceptance rate of virtual network requests, and the hibernation rate of substrate nodes as well as links are improved significantly.

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Authors and Affiliations

Qiang Zhu
Qing-Jun Wang
Mu-Jun Zang
Zhen-Dong Wang
Chang Xiao
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Abstract

The paper concerns the problem of discontinuity in high pressure die castings (HPDC). The compactness of their structure is not perfect, as

it is sometimes believed. The discontinuities present in these castings are the porosity as follow: shrinkage and gas (hydrogen and gas-air

occlusions) origin. The mixed gas and shrinkage nature of porosity makes it difficult to identify and indicate the dominant source. The

selected parameters of metallurgical quality of AlSi9Cu3 alloy before and after refining and the gravity castings samples (as DI - density

index method), were tested and evaluated. This alloy was served to cast the test casting by HPDC method. The penetrating testing (PT) and

metallographic study of both kinds of castings were realized. The application of the NF&S simulation system allowed virtually to indicate

the porosity zones at risk of a particular type in gravity and high-pressure-die-castings. The comparing of these results with the experiment

allowed to conclude about NF&S models validation. The validity of hypotheses concerning the mechanisms of formation and development

of porosity in HPDC casting were also analyzed.

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Authors and Affiliations

Z. Ignaszak
J. Hajkowski
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Abstract

Background: Observing one’s own body has been shown to influence pain perception—a phenomenon called visual analgesia. The effect was originally obtained using a mirror reflection of one’s own hand and later replicated with prosthetic and virtual hands. Most studies show increased pain thresholds during visual analgesia, but the opposite effect can be obtained by inducing ownership illusion over a limb that looks wounded. We tested the hypothesis that a resilient-looking virtual limb would lead to an increased pain threshold.
Methods: Eighty-eight students (Mage = 21.4, SDage = 2.98) participated in a within-group experimental design study (natural hand virtual reality [VR], marble hand VR, and non-VR control). In both VR conditions, a visuo-tactile synchronous stimulation was used to elicit the illusion of embodiment. Pressure pain stimulus was applied to the forearm. Dependent variables were: pressure pain threshold, pain intensity and self-reported embodiment.
Results: There were significant differences between the control condition and the Natural Hand VR (V = 647, p < .0001), and between the control condition and the Marble Hand VR (V = 947.5, p < .005), but not between the Natural Hand and Marble Hand conditions (V = 1428.5, p = .62). Contrary to our predictions, pain threshold was higher in the control condition. Pain intensity differences were not significant.
Conclusions: We obtained a significant effect in the opposite direction than predicted. Such results may mean that the visual analgesia effect is more context-dependent than previously thought. We discuss methodological differences between the paradigm used in this study and paradigms reported in the literature as a possible explanation.
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Authors and Affiliations

Marcin Czub
1
ORCID: ORCID
Joanna Piskorz
1
ORCID: ORCID

  1. Uniwersytet Wrocławski, Instytut Psychologii
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Abstract

In this paper, a novel Power-Frequency Droop Control (PFDC) is introduced to perfectly bring back the system frequency and share the reactive power in isolated microgrid with virtual power plant (VPP). The frequency-based power delivery must be essentially implemented in VPP which can operate as a conventional synchronous generator. It has been attained by enhancing the power processing unit of each VPP to operate as an active generator. The inverter coupling impedance which has been assigned by the virtual impedance technique has reduced the affected power coupling resulting from line resistance. The reference has been subsequently adjusted to compensate the frequency deviation caused by load variation and retrieve the VPP frequency to its nominal value. In addition, the line voltage drop has compensated the voltage drop and load sharing error to obliterate the reactive power sharing imprecision resulting from the voltage deviation. The voltage feedback confirms the correct voltage after compensating the voltage drop. As an illustration, conventional PFDC after a load change cannot restore the system frequency which is deviated from 50 Hz and rested in 49.9 Hz while, proposed PFDC strategy fades away the frequency deviation via compensating the variation of the frequency reference. Likewise, the frequency restoration factor ( γ) has an effective role in retrieving the system frequency, i.e., the restoration rate of the system frequency is in proportion with γ. As a whole, the simulation results have pointed to the high performance of proposed strategy in an isolated microgrid.
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Authors and Affiliations

Amir Khanjanzadeh
1
Soodabeh Soleymani
1
Babak Mozafari
1

  1. Electrical and Computer Engineering Department, Science and Research Branch, Islamic Azad University, Tehran, Iran
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Abstract

The paper tries to defend the thesis that it is impossible to decide upon moral issues without any references to the ontology of the world we live in. An illustrative example of the main argumentation line is the choice made by Cypher—a second plan character in the movie Matrix. Cypher decides to betray human rebels fighting against machines for freedom and, as a reward, accepts affluent life in the virtual reality. His choice seems to be superficially reprehensible because of the abandonment of the real world and authentic life. However, one can argue that the dichotomy between the real and virtual world is seeming. By choosing the virtual reality Cypher decided to act in a world which, like the real world, makes it possible to be a moral subject and enables authentic experience. The difference between both the worlds lies in the type of determination limiting any conscious subject. Cypher prefers to live in a world determined by the algorithm of Matrix more than in a world where his behaviour is determined by genes and other biological factors.

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Authors and Affiliations

Jacek Gurczyński
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Abstract

Congestion is a significant problem affecting the operational processes of a hospital’s outpatient department (OPD). Congestion especially affects the OPD’s architectural space, due to the increased number of patients. Recently, digital tools have been used in healthcare systems to reduce congestion and help the OPD improve its operational processes; one of these tools is the virtual examination room. However, patients still need to be examined by physicians in the OPD, and digital tools alone cannot solve all the problems that congestion creates. The authors of this paper conducted a study that offers a new way to alleviate congestion in the OPD by combining physical and digital solutions to increase OPD efficiency and optimize its operational processes. The study created an alternative operational plan that adds virtual examination rooms to reduce congestion. This plan allows the OPD to increase the number of physical and virtual examination rooms by almost 110% and increase the number physically and virtually examined patients by 153% each day. The plan also redesigns some architectural spaces at the OPD to enhance the environment and match the hospital’s requirement for authorized bodies.
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Authors and Affiliations

Waleed Ben Saeed
1
ORCID: ORCID
Yasser Adas
1
ORCID: ORCID
Ayad Almaimani
1
ORCID: ORCID

  1. King Abdulaziz University Faculty of Architecture and Planning Department of Architecture
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Abstract

The impact of casting conditions on microstructure a and mechanical properties was described, especially for cast products from AlSi9Cu3 alloy. Particular attention was paid to the parameters of dendritic structure: DAS 1 and DAS 2. Selected mechanical properties (by static tension test) of test castings made using basic technologies of casting: GSC - gravity sand casting, GDC - gravity die-casting and HPDC - high-pressure die-casting, are presented for cast-on test bars and cast separately. Casts were made of the same alloy AlSi9Cu3. Fractures and the zone near the fracture (after static tension test) was subjected to VT - visual tests, PT - penetration tests and metallographic tests. The condition of porosity (fracture zone) was also assessed. The analysis of virtual results was performed using the NovaFlow & Solid system together with the database and they were compared to experimental tests. This way of validation was applied in order to assess the correlation between the local rate of cooling and the size of DAS for GSC, GDC and HPDC technologies. Finally, the correlation between the parameters of structure and mechanical properties with regard to the impact of porosity was signalized.

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Authors and Affiliations

J. Hajkowski
Z. Ignaszak
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Abstract

Background. For many years virtual reality (VR) has been used to support therapy in many clinical contexts. This study aimed to investigate the effectiveness of VR as an intervention to reduce distress and increase patient comfort during chemotherapy. Participants and Procedure. Twenty-six adult patients of the Haematology Clinic participated in the between-group design study. The experimental group used a VR application during three chemotherapy sessions, while the control group underwent treatment as usual.
Participants' task in VR was to locate and destroy cancer cells using drug particles emitted from a virtual weapon. Several self-report measures were used, measuring attitudes towards the chemotherapy session, experiences during the session, items related to using visualization techniques, and questions related to evaluating the VR application.
Results. We found a significant difference between groups regarding the experience of the session. Participants in the experimental group reported more sense of control over the treatment process, higher levels of physical comfort, and relaxation. We discuss the implications of these results in various contexts, including gender differences, age, and time between chemotherapy sessions.
Conclusions. Virtual Reality applications can effectively influence the experience of the chemotherapy session positively. Its use can also affect the psychological aspects of a patient's treatment process.
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Authors and Affiliations

Joanna Piskorz
1
ORCID: ORCID
Marcin Czub
1
ORCID: ORCID
Magdalena Mróz
1
ORCID: ORCID
Jarosław Drapała
2
ORCID: ORCID

  1. Uniwersytet Wrocławski, Wroclaw, Poland
  2. Politechnika Wrocławska, Wroclaw, Poland
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Abstract

The relevance of the study is due to the fact that the influence of the Internet and media resources is growing and there is a tendency to develop virtual personalities that have little to do with reality and show the features of an antisocial person. In this regard, this article is aimed at identifying aspects and characteristics of a network personality that is influenced by modern media resources. The leading methods of studying this problem are methods of analysis, deduction and classification, which will help to recognize the most basic aspects of the figurative-visual transformation of a person on the Internet, show the results of the influence of social networks on a person and demonstrate the changes that a person is exposed to in the Internet space. The article reveals and substantiates the features and aspects that are distinctive for an individual in the Internet society, negative and positive characteristics of Internet users. The author substantiates the daily interactivity of social media. Also, the most relevant and influential forms of network interaction are shown and the frequency of their use is analysed. The materials of the article are of practical value for students, teenagers, youth, parents, future teachers who should know the aspect of the manifestation of personality transformation in the Internet space.
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Authors and Affiliations

Elissa Bagayeva
1

  1. Individual Entrepreneur Bagayeva Elissa Petrovna, Otegen Batyr, Republic of Kazakhstan
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Abstract

The present study aimed to investigate the effects of manipulating visual information about one’s movement in Virtual Reality (VR) during physical training on a stationary bike. In the first experiment, the participants’ (N=30) task was to cycle on a stationary bike while embodying a virtual avatar. Fifteen participants experienced the Slow condition, in which a virtual avatar cycled at the constant speed of 15km/h, while the other fifteen participants experienced the Fast condition, in which a virtual avatar cycled at the constant speed of 35km/h. In the second experiment, we tested whether introducing agency (i.e., linking real-life cycling speed with the cycling speed of a virtual avatar), would improve exercise performance. Participants (N=31) experienced counterbalanced conditions: Faster optic flow (avatar’s speed was 15% faster than the participants’ real cycling speed), and Slower optic flow (avatar’s speed was 15% slower than the participants’ real cycling speed). Results showed that all participants increased their cycling speed when experiencing altered cycling speed of a virtual avatar compared with their baselines, but in the first experiment, participants cycled faster in the faster optic flow condition, while in the second experiment, when participants controlled the virtual avatar’s cycling speed, there were no differences between the Fast and Slow conditions. Participants described the cycling in VR as a pleasant experience. The present study suggests that the addition of Virtual Reality during exercise training may increase cycling performance.
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Authors and Affiliations

Marta Kowal
1
ORCID: ORCID
Joanna Piskorz
1
ORCID: ORCID
Marcin Czub
1
ORCID: ORCID

  1. Institute of Psychology, University of Wrocław, Poland
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Abstract

The goal of this study was to test the efficacy of a tactile attention distraction from pain and compare its effectiveness with a virtual reality (VR) distraction on an analogous task. VR is considered to be the gold standard for attention distraction, but it cannot be used in certain clinical cases or for particular medical procedures. A repeatedmeasures experimental study was carried out with 42 participants using tactile and VR variants of an n-back task and a cold pressor test for pain. The independent variable was the distraction type (tactile, VR, or no-distraction) and the dependent variable was pain tolerance (i.e., time participants kept their hand in cold water). The results showed that both tactile and VR games effectively increased pain tolerance compared to the control condition. Effect sizes for both interventions were similar. However, the effect was observed only for female participants.
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Authors and Affiliations

Marcin Czub
1
ORCID: ORCID
Anna Bagrij
1

  1. Institute of Psychology, University of Wrocław
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Abstract

Virtual reality (VR) technology now provides players with immersive and realistic experiences as never before. Spatial presence plays a crucial role in the introduction of immersive experience in a VR environment. Spatial presence is a special feeling of personal and physical presence in the displayed environment. In this study, we found that the first-person perspective (1PP) was more effective in raising the sense of spatial presence that induces immersive experience compared to the third-person perspective (3PP) in a VR shooting game. Moreover, eye blink rate was significantly higher in the 1PP compared with the 3PP. The 1PP game setting was more realistic than the 3PP setting, and may have raised participants’ sense of immersion and facilitated eye blink. These results indicate that eye blink rate is increased by the sense of spatial presence, and can be a good measure of subjective immersive experience in a VR environment. Neuroscientific evidences suggest that dopaminergic system is involved in such emotional experiences and physiological responses.

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Authors and Affiliations

Tomohide Ishiguro
Cohta Suzuki
Hiroki Nakakoji
Yusuke Funagira
Motoharu Takao
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Abstract

Using the tunderwater corner reflector (CR) to simulate the acoustic scattering characteristics of the military target is a new technology to counter active sonar detection. Existing underwater CRs only have the ability to interfere with the acoustic field, but have limitations in acoustic wave modulation. Therefore, acoustic metasurfaces applied on CRs to enhance the ability of acoustic wave modulation has a great application prospect. A fast prediction method based on the Kirchhoff approximation (KA) and the ray tracing theory is proposed to calculate the acoustic scattering characteristics of CR with acoustic metasurfaces in grooves array type. The accuracy of the method is verified by the finite element method (FEM) simulation. The modulation effect of CR with grooves array in different gradient combinations on the structural scattering acoustic field is analyzed. The research shows that the CR with different combinations of the acoustic metasurface has an obvious modulation effect on the amplitude of the acoustic waves and the deflection of acoustic field. In particular, the grooves array in combination with positive and negative gradients has an obvious deflection impact on the scattering acoustic field.
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Authors and Affiliations

Jiaman Du
1
Zilong Peng
1
Lili Ge
1
Shijin Lyu
1 2
Fulin Zhou
3
Yan Liu
4
ORCID: ORCID

  1. School of Energy and Power Engineering Jiangsu University of Science and Technology, Zhenjiang, China
  2. National Key Laboratory on Ship Vibration and Noise, China Ship Science Research Center, Wuxi, China
  3. School of Naval Architecture, Ocean and Civi Engineering, Shanghai Jiao Tong University, Shanghai, China
  4. Shanghai Research Institute of Materials, Shanghai, China
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Abstract

The paper aims at the higher reactive power management complexity caused by the access of distributed power, and the problem such as large data exchange capacity, low accuracy of reactive power distribution, a slow convergence rate, and so on, may appear when the controlled objects are large. This paper proposes a reactive power and voltage control management strategy based on virtual reactance cloud control. The coupling between active power and reactive power in the system is effectively eliminated through the virtual reactance. At the same time, huge amounts of data are treated to parallel processing by using the cloud computing model parallel distributed processing, realize the uncertainty transformation between qualitative concept and quantitative value. The power distribution matrix is formed according to graph theory, and the accurate allocation of reactive power is realized by applying the cloud control model. Finally, the validity and rationality of this method are verified by testing a practical node system through simulation.

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Authors and Affiliations

Wei Min Zhang
Yan Xia Zhang
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Abstract

The neutral point clamped (NPC) three-level inverter is widely used in highvoltage and high-power applications. However, neutral point voltage oscillation (NPVO) and common-mode voltage (CMV) problems exist in the NPC three-level inverter. In this paper, an improved virtual space vector modulation (VSVM) is proposed based on the reconstruction of a virtual small vector and a virtual medium vector. Compared with the traditional VSVM, an improved VSVM can effectively reduce the CMV. On this basis, a vector conversion method is proposed to further reduce the NPVO in the whole range. Simulation results verify the effectiveness and superiority of the improved VSVM.
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Bibliography

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[5] Li C., Yang T., Kulsangcharoen P., Lo Calzo G., Bozhko S., Gerada C., Wheeler P., A Modified Neutral-Point Balancing Space Vector Modulation for Three-Level Neutral Point Clamped Converters in High Speed Drives, IEEE Trans. Ind. Electronics, vol. 66, no. 2, pp. 910–921 (2019).
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[14] Xiang C.Q., Shu C., Han D., Improved Virtual Space Vector Modulation for Three-Level Neutral- Point-Clamped Converter with Feedback of Neutral-Point Voltage, IEEE Trans. Power Electronics, vol. 33, no. 6, pp. 5452–5464 (2018).
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[20] Xu X., Zheng Z., Wang K., Yang B., Li Y., A Comprehensive Study of Common Mode Voltage Reduction and Neutral Point Potential Balance for a Back-to-Back Three-Level NPC Converter, IEEE Trans. Power Electronics, vol. 35, no. 8, pp. 7910–7920 (2020).
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Authors and Affiliations

Junlong Fang
1
ORCID: ORCID
Guangya Wang
1
Ran Li
1
Siyuan Liu
1
Shuyu Wang
1

  1. School of Electricity and Information, Northeast Agricultural University, China
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Abstract

Renewable energy sources are connected to the grid through inverters, resulting in reduced grid inertia and poor stability. Traditional grid-connected inverters do not have the function of voltage and frequency regulation and can no longer adapt to the new development. The virtual synchronous generator (VSG) has the function of voltage and frequency regulation and has more outstanding advantages than the traditional inverter. Based on the principle of the VSG, the relationship between energy storage capacity, frequency response and output power of the VSG is derived, and the relationship between the virtual inertia coefficient, damping coefficient and frequency characteristics of the VSG and output power is revealed. The mathematical model is established and modeled using the Matlab/Simulink simulation software, and the simulation results verify the relationship between energy storage capacity and frequency response and the output power of the VSG.
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Authors and Affiliations

Baoge Zhang
1
ORCID: ORCID
Shanyan Ping
1
Yi Long
1
Yuemin Jiao
1
Boxiang Wu
1

  1. School of Automation and Electrical Engineering, Lanzhou Jiaotong University, China
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Abstract

The existence of inrush current poses a significant problem during the start-up process within three-phase voltage-source rectifiers. To address this problem, this study proposes a strategy to suppress the inrush current effectively based on the virtual-resistor- control method, while preventing the increase in cost of the system and complexity of the algorithm. First, a mathematical model is established based on the dq coordinate frame, and the primary cause of the inrush current is analyzed. Then, the design process of the virtual-resistor-control method is detailed. Finally, the accuracy and effectiveness of the proposed method are verified by simulations and experiments. The results show that the inrush current can be more than two times the rated current before the addition of the virtual resistor. The start-up process can be realized without the inrush current after the addition of the virtual resistor, it does not need to increase hardware costs, there is no secondary inrush current, and the sensitivity of the parameters and the complexity of control are low.

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Authors and Affiliations

Kaizhong He
Hongsheng Su
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Abstract

This paper proposes an electromechanical transient method to build a battery energy storage system-based virtual synchronous generator model, suitable for a large-scale grid. This model consists of virtual synchronous generator control, system limitation and the model interface. The equations of a second-order synchronous machine, the characteristics of charging/discharging power, state of charge, operating efficiency, dead band and inverter limits are also considered. By equipping the energy storage converter into an approximate synchronous voltage source with an excitation system and speed regulation system, the necessary inertia and damping characteristics are provided for the renewable energy power system with low inertia and weak damping. Based on the node current injection method by the power system analysis software package (PSASP), the control model is built to study the influence of different energy storage systems. A study on the impact of renewable energy unit fluctuation on frequency and the active power of the IEEE 4-machine 2-area system is selected for simulation verification. Through reasonable control and flexible allocation of energy storage plants, a stable and friendly frequency environment can be created for power systems with high-penetration renewable energy.
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Authors and Affiliations

Juntao Cui
1
Zhao Li
2
ORCID: ORCID
Ping He
2
ORCID: ORCID
Zhijie Gong
2
Jie Dong
2
ORCID: ORCID

  1. Lanzhou Resources and Environment Voc-Tech University, China
  2. Zhengzhou University of Light Industry, China
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Abstract

In recent years, many scientific and industrial centres in the world developed a virtual reality systems or laboratories. The effect of user “immersion” into virtual reality in such systems is largely dependent on optical properties of the system. In this paper, problems of luminance distribution uniformity in CAVE-type virtual reality systems are analyzed. For better characterization of CAVE luminance nonuniformity corner and edge CAVE nonuniformity were introduced. Based on described CAVE-type virtual reality laboratory, named Immersive 3D Visualization Lab (I3DVL) just opened at the Gdansk University of Technology, luminance nonuniformity of the system is evaluated and discussed. Data collection of luminance distribution allows for software compensation of intensity distribution of individual images projected onto the screen (luminance non-uniformity minimization) in the further research.

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Authors and Affiliations

A. Mazikowski
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Abstract

The present paper is concerned with the practical interconnection between virtual engineering tools and additive model manufacturing technologies and the subsequent production of a ceramic shell by rapid prototyping with the use of Cyclone technology to produce the aluminium casting prototype. Prototypes were developed as part of the student formula project, where several parts originally produced by machining were replaced by castings. The techniques of topological optimization and the combination with the tools of the numerical simulation were used to optimise the virtual prototype before a real production of the first prototype. 3D printing of wax pattern ensured direct and fast assembly of the cluster without any additional operations and troubles during dewaxing. The shell was manufactured in 6 hours thanks to a system of quick-drying of individual layers of ceramic shell. It has been verified that the right combination of individual virtual tools with the rapid prototyping can shorten the development time and delivery of the first prototypes from a few months to a few weeks.
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Bibliography

[1] Xiao, A., Bryden, K.M. (2004). Virtual engineering: A vision of the next-generation product realization using virtual reality technologies. Proceedings of the ASME 2004 Design Engineering Technical Conferences – DETC’04, 28 September – 2 October, pp 1-9.Salt Lake City, Utah, #57698.
[2] Pekkola, S. & Jäkälä, M. (2007) From technology engineering to social engineering: 15 years of research on virtual worlds. The DATA BASE for Advances in Information Systems. 38(4), 11-16.
[3] Bao, Jin, J.S., Gu, Y., Yan, M.Q. & Ma, J.Q. (2002). Immersive virtual product development. Journal of Materials Processing Technology. 129(1-3), 592-596. DOI: 10.1016/S0924-0136(02)00655-6.
[4] Van der Auweraer, H. (2010). Virtual engineering at work: The challenges for designing intelligent products. In: Proceedings of the TMCE 2010 Symposium, April 12-16, (pp. 3-18), Ancona, Italy.
[5] Stawowy, A., Wrona, R., Brzeziński, M. & Ziółkowski, E. (2013). Virtual factory as a method of foundry design and production management. Archives of Foundry Engineering. 13(1), 113-118. DOI: 10.2478/afe-2013-0022
[6] Dépincé, P., Chablat, D., Woelk, P.O. (2004) Virtual manufacturing: tools for improving design and production, Dans International Design Seminar - CIRP International Design Seminar, Egypt.
[7] Kumar, P., Ahuja, I.P.S. & Singh, R. (2013). Framework for developing a hybrid investment casting process. Asian Review of Mechanical Engineering, 2(2), 49-55.
[8] Kügelgen, M. (2008). From 7 days to 7 hours – Investment casting parts within the shortest time, 68th WFC - World Foundry Congress, 7th - 10th February, 2008, (pp. 147-151).

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Authors and Affiliations

V. Krutiš
1
ORCID: ORCID
P. Šprta
1
V. Kaňa
1
ORCID: ORCID
A. Zadera
1
J. Cileček
2

  1. Brno University of Technology, Czech Republic
  2. Alucast s.r.o., Czech Republic
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Abstract

Adjustable-width pulse signals are widely used in systems such as test equipment for hold time, response time and radar testing. In this study, we proposed a pulse generation method based on virtual sampling with ultra-high pulse width resolution. In the proposed method, the sampling rate of a digital-to-analogue converter (DAC) was adjusted to considerably improve pulse width resolution. First, the sampling rate was matched with the target pulse width resolution to digitally sample the ideal signal and generate digital waveform sampling points. Next, the signal bandwidth of the DAC was matched using a low-pass digital filter. Finally, the waveform sampling points were downsampled using an integer factor and output after digital-to-analogue conversion. The waveform pulse width information generated by high-frequency digital sampling was passed step by step and retained in the final output analogue signal. A DAC with a sampling rate of 1.25 GSa/s was used, and the pulse width resolution of the pulse signal was 0.1 ns. Theoretically, a sampling rate of 10 GSa/s is required to achieve 0.1 ns resolution. This method is simple, has a low cost, and exhibits excellent performance.
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Authors and Affiliations

Hanglin Liu
1
Zaiming Fu
1
Dexuan Kong
1
Houjun Wang
1
Yindong Xiao
1

  1. University of Electronic Science and Technology of China, School of Automation Engineering, Chengdu 611731, China
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Abstract

Numerous technological applications use MEMS capacitive sensing technique as a major component, because of their ease of fabrication process, inexpensive and high sensitivity. The paper aims at modeling interdigitated capacitive (IDC) sensing. Virtually observe the contribution of variations in geometrical parameters to sensor efficiency and optimization factor. The sensor design is verified through ANSYS simulations. Results indicate “an efficient but poorly optimized sensor is better than a well-optimized sensor”. It is difficult to detect capacitance in the range of few pF generated using capacitive sensing. How it can be maximized with dimension optimization is focused in this paper.
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Authors and Affiliations

Vaishali Sanjay Kulkarni
1
Suvarna Sandip Chorage
2

  1. Department of E&TC at AISSMSIOIT-Pune,India
  2. Department of E&TC at BVCOEW-Pune, India
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Abstract

There is a discrepancy between the research exploring e-learning at medical universities in Central/Eastern and Western European countries. The aim of the MeSPeLA study was to explore the understanding, experience and expectations of Polish medical students in terms of e-learning. Questionnaire containing open-ended and closed questions supplemented by focus group discussion was validated and performed among 204 medical students in Poland before COVID-19 pandemia. Several domains: understanding of e-learning definitions; students’ experience, preferences, expectations and perceptions of e-learning usefulness, advantages and disadvantages were addressed. The qualitative data were analyzed using an inductive approach. 46.0% of students chose a communication-oriented definition as the most appropriate. 7.4% claimed not to have any experience with e-learning. 76.8% of respondents indicated they had contact with e-learning. The main reported e-learning advantages were time saving and easier time management. The most common drawback was limited social interactions. The acceptance of the usage of e-learning was high. Medical undergraduates in Poland regardless of the year of studies, gender or choice of future specialization showed positive attitudes towards e-learning. Students with advanced IT skills showed a better understanding of the e-learning definition and perceived e-learning to be a more useful approach. The expectations and perceptions about e-learning in Polish medical schools seems similar to some extent to that in Western European and the United States so we can be more confident about applying some lessons from these research to Poland or other post-communist countries. Such application has been accelerated due to COVID-19 pandemia.
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Authors and Affiliations

Mirosława Püsküllüoğlu
1
Michał Nowakowski
2
Sebastian Ochenduszko
3
David Hope
4
Helen Cameron
5

  1. Department of Clinical Oncology, Maria Sklodowska-Curie National Research Institute of Oncology, Cracow Branch, Kraków, Poland
  2. 2nd Department of General Surgery, Jagiellonian University Medical College, Kraków, Poland
  3. Department of Medical Oncology, Hospital Universitario Dr Peset, Valencia, Spain
  4. Centre for Medical Education, The Chancellor’s Building, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh, Scotland
  5. Aston Medical School, Aston University, Birmingham, UK

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