A method for discrete event simulation and building information modelling integration using a game engine

Sandoval, Carlos A. Osorio,Tizani, Walid,Koch, Christian Techno-Press 2018 Advances in computational design Vol.3 No.4

Building Information Modelling (BIM) and Discrete Event Simulation (DES) are tools widely used in the context of the construction industry. While BIM is used to represent the physical and functional characteristics of a facility, DES models are used to represent its construction process. Integrating both is beneficial to those interested in the field of construction management since it has many potential applications. Game engines provide a human navigable 3D virtual environment in which the integrated BIM and DES models can be visualised and interacted with. This paper reports the experience obtained while developing a simulator prototype which integrates a BIM and a DES model of a single construction activity within a commercial game engine. The simulator prototype allows the user to visualise how the duration of the construction activity is affected by different input parameters interactively. It provides an environment to conduct DES studies using the user's own BIM models. This approach could increase the use of DES technologies in the context of construction management and engineering outside the research community. The presented work is the first step towards the development of a serious game for construction management education and was carried out to determine the suitable IT tools for its development.

Reduced Active Switch Front-End Multipulse Rectifier With Medium-Frequency Transformer Isolation

Sandoval, Jose Juan,Krishnamoorthy, Harish Sarma,Enjeti, Prasad N.,Choi, Sewan IEEE 2017 IEEE TRANSACTIONS ON POWER ELECTRONICS - Vol.32 No.10

<P>This paper presents a reduced switch count multipulse rectifier with medium-frequency (MF) transformer isolation. The proposed topology consists of a three-phase push-pull based ac to dc rectifier with a MF ac link employing two active switches. A three-phase, five-limb, multiwinding MF transformer is employed for isolation. The secondary side of the transformer is connected in a zig-zag configuration and is fed to two six-pulse diode rectifiers, achieving 12-pulse rectifier operation. The primary advantage of the proposed system is reduction in size/weight/volume compared to the conventional 60 Hz magnetic transformer isolation rectifier system. Operating the transformer at 600 Hz is shown to result in three times reduction in size. Furthermore, the proposed system employs only two active semiconductor switching devices operating under a simple pulse width modulation scheme. Also, the zig-zag transformer connection helps to balance leakage inductance on the secondary side. Detailed analysis, simulation, and experimental results on a 208V(l-l), 3.15 kW laboratory prototype are presented to validate the performance of the proposed approach.</P>

Safety and immunogenicity of different booster vaccination schemes for COVID-19 used in El Salvador

Sandoval Xochitl,Domínguez Rhina,Recinos Delmy,Zelaya Susana,Cativo Patricia,Docena Guillermo Horacio 대한백신학회 2024 Clinical and Experimental Vaccine Research Vol.13 No.1

Purpose: The effectiveness of coronavirus disease 2019 (COVID-19) vaccination schemes and the combination of vaccines of various platforms for administering booster doses is still being studied since it will depend on the population’s response to vaccines. We aimed to evaluate the safety, protection, and immunogenicity of the Salvadorean population’s third dose booster COVID-19 vaccine and the potential benefit of homologous vs. heterologous regimens. Materials and Methods: This is an analytical observational cohort study in a population aged 18 to 65 years that was primarily vaccinated with AstraZeneca, Sinovac, or Pfizer/BioNTech. Volunteers were recruited (n=223) and followed up for 3 months after receiving the 3rd vaccine (BNT162b2) as a booster. Adverse reactions were monitored, serum anti-spike immunoglobulin G (IgG) was assessed by chemiluminescence, and a polymerase chain reaction was carried out when subjects developed clinical signs. Results: The cohorts finally included 199 participants, and we observed only mild adverse effects in all cohorts. A significant increase in specific IgG levels was found after the booster dose in all cohorts. The heterologous scheme with Sinovac showed the greatest increase in antibody titer, and a decrease was observed in all participants after 3 months. During the follow-up period, 30 participants showed symptomatology compatible with COVID-19, but only four were laboratory-confirmed and they showed mild clinical signs. Conclusion: These findings indicate that the booster doses used were safe and promoted an immediate increase in immunogenicity, which decreased over time. The heterologous regimen showed stronger immunogenicity compared to the messenger RNA-based homologous scheme.

Complete decentralized displacement control algorithm

Ruiz-Sandoval, M.E.,Morales, E. Techno-Press 2013 Smart Structures and Systems, An International Jou Vol.11 No.2

Control systems have been greatly studied in recent years and can be classified as: passive, active, semi-active or hybrid systems. Most forms of control systems have been applied in a centralized manner where all the information is sent to a central node where control the algorithm is then calculated. One of the possible problems of centralized control is the difficulty to scale its application. In this paper, a completely decentralized control algorithm is analytically implemented. The algorithm considers that each of the control systems makes the best decision based solely on the information collected at its location. Semi-active control is used in preference to active control because it has minimal energy consumption, little to no possibility of destabilization, a reduction in the possibility of data saturation, and a reduction in the response time in comparison to centralized control.

Factors and conditions promoting academic resilience: a TIMSS-based analysis of five Asian education systems

Andrés Sandoval-Hernández,Piotr Białowolski 서울대학교 교육연구소 2016 Asia Pacific Education Review Vol.17 No.3

It is well documented that academic achievement of students from families of low socioeconomic status (SES) tends to be below their more socially advantaged peers. Several studies have identified factors and conditions that facilitate academic success for disadvantaged students (i.e., promote academic resilience). However, one of the main criticisms of this body of research is in the set of variables that explain academic success for low-SES students and which is not very different from the variables that would explain academic success for all students. The objectives of this article are dual: firstly, to identify factors and conditions associated with academic success, regardless of student SES, and secondly, to identify factors and conditions associated with academic resilience, that is, exclusively for low-SES students. To this end, we used data from Singapore, South Korea, Hong Kong, Chinese Taipei, and Japan in the Trends in International Mathematics and Science Study (TIMSS) 2011. The study sample covered 23,354 students in 720 schools in the five countries. The strategy for analysis was driven by fit of logistic regression models, first predicting the probability of academic success and then subsequent identification of variables significant as predictors for success within the pool of low-SES students. Results indicated that variables, such as positive student attitude to mathematics, teacher confidence in student performance and the test language being spoken at home, were associated with greater chances of academic success. High academic expectations and time spent on mathematics at home demonstrated a differential effect between disadvantaged and non-disadvantaged students in Singapore. In Korea, being male (gender) and in Taipei, low levels of bullying at school, increased the likelihood of resilience. Results suggested that interventions impacting behavior reflected in differentially associated variables could help disadvantaged students to become academically resilient.

An Output Feedback Position/Speed Regulator for a Torque–driven Inertia Wheel Pendulum

Jesús Sandoval,Rafael Kelly,Víctor Santibáñez 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.10

This paper presents a position/speed regulator for a torque–driven inertia wheel pendulum where only position measurements are available for feedback. Our contribution is to introduce a controller that does not need joint velocity measurements, and instead it uses the output of a linear filtering of weighted joint position errors to add damping. The proposed controller allows bringing the nonactuated pendulum rod towards its upright position, while the wheel spins asymptotically to a desired constant speed. A complete stability analysis based on Barbashin–Krasovskii’s theorem is presented together with an estimate of domain of attraction. Simulation results upon a torque–driven inertia wheel pendulum model illustrate the performance of the proposed controller.

Comparison of Different Models for Energy Dissipation in Unsteady Flows

Ramon Sandoval Pena,Alex Anderson 대한기계학회 1993 International Symposium on Transport Phenomena in Vol.3 No.1

Resonance of a flexible plate immersed in a von Kármán vortex street

Erika Sandoval Hernández,Stefan G. Llewellyn Smith,Anne Cros 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.4

This work presents a theoretical and experimental study of a flexible plate immersed in a von Kármán vortex street. The wake is generated in a water flow using a cylindrical obstacle with a Reynolds number lower than 200. The vortices provoke oscillations of a flexible plate whose leading edge is clamped a few cylinder diameters downstream of the obstacle. The oscillation amplitude of the free edge is examined experimentally as the plate length is varied with respect to the wavelength. The value of the peak of the amplitude and the phase shift between the forcing vortices and the plate deflection are consistent with theoretical predictions. These predictions use an Euler-Bernoulli model for the motion of the plate produced by the pressure difference over the plate due to the combined effect of the vortex street and the deflection of the plate. The ratio between the plate length and the wake wavelength for which resonance occurs is fixed by the condition that the natural frequency of the plate is equal to the vortex frequency.

Efficacy of physical and chemical treatments on the inactivation of bovine leukosis virus present in milk

Rocío Silvia Sandoval-Monzón,Irma Cecilia Karla Arévalo-Rodriguez,Aldo Alberto Carrillo-Torres,Luis Felipe Ruiz-García 대한백신학회 2021 Clinical and Experimental Vaccine Research Vol.10 No.1

Purpose: The objective of the present study was to evaluate the efficacy of pasteurization, freezing, the addition of formaldehyde and peroxymonosulfate on the inactivation of the bovine leukemia virus (BLV) present in milk. Materials and Methods: A sheep bioassay was carried out in 40 sheep, which were intraperitoneally inoculated with leukocytes from milk infected by the BLV previously treated with one of the virus inactivation methods. Five study groups were evaluated: (1) control group: milk without previous treatment, (2) pasteurization group: milk treated by pasteurization, (3) freezing group: milk treated by freezing for 36 hours, (4) formaldehyde group: 0.1% formaldehyde, and (5) peroxymonosulfate group: 0.05% peroxymonosulfate. The inoculated animals were followed for 10 weeks. Results: At week 10 post-inoculation, all the animals (8/8) of the control group and the peroxymonosulfate group were seropositive to BLV, while no animals were seropositive (0/8) to BLV in the remaining three groups. Statistically significant differences were found between the pasteurization, freezing and formaldehyde groups with respect to the control (p<0.001) and peroxymonosulfate groups (p<0.001). Conclusion: The results indicate that pasteurization, freezing and formaldehyde processes are efficient in inactivating the BLV and can be used in milk to prevent the transmission of the virus.

In Vitro Bioaccessibility and Effect of Mangifera indica (Ataulfo) Leaf Extract on Induced Dyslipidemia

Eli Mireya Sandoval-Gallegos,Esther Ramı´rez-Moreno,Juan Gayosso-De Lucio,Jose´ Arias-Rico,Nelly Cruz-Cansino,Mario I. Ortiz,Raquel Carin˜o-Corte´s 한국식품영양과학회 2018 Journal of medicinal food Vol.21 No.1

Cardiovascular diseases (CVDs) are the leading causes of death in the world, and epidemiological evidence points to dietary habits, stress, and obesity as major risk factors promoting pathological conditions like atherosclerosis, hypertension, and thrombosis. Current therapeutic approaches for CVDs rely on lifestyle changes and/or the use of drug agents. However, since the efficacy of such interventions is often limited by poor compliance and/or significant side effects, continued research on new preventive and therapeutic approaches is much needed. Our study is aimed to determine the bioaccessibility, total content of phenolic compounds, and antioxidant capacity (DPPH·, ABTS·+) of a methanolic extract from Mangifera indica L. leaves (MEM), and its lipid-lowering effect on an induced dyslipidemia model in Wistar rats. Our results showed that mangiferin is the main component of MEM. The extract showed a total content of polyphenol compounds of 575.28 gallic acid equivalents per dry matter basis (GAE/g db), antioxidant activity 77.68 μmol Trolox equivalents per gram (TE/g) db as measured by DPPH· and 20,630 μmol TE/g db by ABTS·+, and 12% of phenolic compounds were bioaccessible, and 100 mg/kg of MEM reduced hyperlipidemia levels induced in Wistar rats. Further study on the potential use of MEM as a nutraceutical to prevent CVDs in high-fat diet consumers is required.