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Relay-assisted multiuser MIMO-DQSM system for correlated fading channels
Francisco R. Castillo-Soria,Carlos Gutierrez,Fermin M. Maciel-Barboza,Viktor I. Rodriguez Abdala,Jayanta Datta 한국전자통신연구원 2024 ETRI Journal Vol.46 No.2
This paper presents the performance evaluation of an amplify-and-forward (AF) relay-assisted multiuser multiple input-multiple output (MU-MIMO) downlink transmission system for correlated fading channels. The overall system performance was improved by incorporating a double-quadrature spatial modulation (DQSM) scheme. The bit error rate (BER) performance and detection complexity of the AF-MU-MIMO-DQSM system were analyzed and com-pared with those of a conventional AF-MU-MIMO system under the same conditions and parameters. The results showed that the correlated fading channel severely affected the performance of systems with higher spectral efficiency (SE). Considering an SE of 12 bpcu/user, the AF-MU-MIMO-DQSM system yielded a gain of up to 3 dB in BER performance compared with that of its conventional counterpart for the analyzed cases. In terms of detection com-plexity, the AF-MU-MIMO-DQSM system showed a reduction of up to 56 % compared with that of the conventional system for the optimal maximum likelihood detection criterion.
Personal Exposure to PM2.5 in the Massive Transport System of Bogotá and Medellín, Colombia
Maria Paula Castillo-Camacho,Isabel Cristina Tunarrosa-Grisales,Lina María Chacón-Rivera,Marco Andrés Guevara Luna,Luis Carlos Belalcázar Cerón 한국대기환경학회 2020 Asian Journal of Atmospheric Environment (AJAE) Vol.14 No.3
Recent studies have shown that public transport users can be exposed to high levels of pollution emitted from their own vehicles and nearby sources. The purpose of this research is to determine the personal exposure of passengers to PM2.5 inside the vehicles of the massive public transport of two of the main and more populated cities of Colombia, Bogotá and Medellín. TM (TransMilenio powered by diesel) and SITVA (electric and gas natural vehicles) were the systems studied. Were evaluated the integration of new vehicles with technologies Euro V and Euro VI in the TM system, the impact of the weekend effect on personal exposure into public transport(TM and SITVA), and the possible differences between personal exposure regarding the ways of the systems(mixed lane or exclusive lane for TM and SITVA). To measure PM2.5 levels, a DustTrak monitor previously calibrated was used. This measurement campaigns lasted for more than 80 hours and a mean of 17000 data of PM2.5 concentrations were obtained for each route. The personal dose was calculated based on the recorded data. The mean PM2.5 concentrations and personal dose found in the research for TM are 167 µg/m³ and 2.3 µg/min, respectively, while, for SITVA they are 41 µg/m³ and 0.53 µg/min, respectively. Therefore, SITVA users have a 5 times lower personal exposure to PM2.5 than TM users. It was also found that due to the poor proportion of new TM vehicles during the monitoring period, the personal exposure in the old vehicles and in the new ones is similar. In the case of SITVA, it was evidenced that the mixed lane contributes to a high personal exposure to PM2.5 than the exclusive one.
Liver transplantation for hepatocellular carcinoma at Centro Médico Nacional 20 de Noviembre-México
Alberto DE JESUS-FLORES,Carlos FLOREZ-ZORRILLA,Ricardo CERON-CASTILLO,Carlos VAZQUEZ-SALINAS,Nadia ROMERO-BEYER,Aczel SANCHEZ-CEDILLO,Miguel CHARCO-CRUZ 한국간담췌외과학회 2021 Annals of hepato-biliary-pancreatic surgery Vol.25 No.-
Concept Design and Performance Evaluation of UAV-based Backhaul Link with Antenna Steering
Jiri Pokorny,Aleksandr Ometov,Pablo Pascual,Carlos Baquero,Pavel Masek,Alexander Pyattaev,Ainoa Garcia,Carlos Castillo,Sergey Andreev,Jiri Hosek,Yevgeni Koucheryavy 한국통신학회 2018 Journal of communications and networks Vol.20 No.5
At present, cellular coverage in many rural areas remainsintermittent. Mobile operators may not be willing to deployexpensive network infrastructure to support low-demand regions. For that reason, solutions for the rapid deployment of base stationsin areas with insufficient or damaged operator infrastructureare emerging. Utilization of unmanned aerial vehicles (UAVs) ordrones serving as data relays holds significant promise for deliveringon-demand connectivity as well as providing public safety servicesor aiding in recovery after communication infrastructure failurescaused by natural disasters. The use of UAVs in provisioninghigh-rate radio connectivity and bringing it to remote locations isalso envisioned as a potential application for fifth-generation (5G)communication systems. In this study, we introduce a prototypesolution for an aerial base station, where connectivity between adrone and a base station is provided via a directional microwavelink. Our prototype is equipped with a steering mechanism drivenby a dedicated algorithm to support such connectivity. Our experimentalresults demonstrate early-stage connectivity and signalstrength measurements that were gathered with our prototype. Our results are also compared against the free-space model. Thesefindings support the emerging vision of aerial base stations as partof the 5G ecosystem and beyond.
Reuse of Steel in the Construction Industry: Challenges and Opportunities
Alper Kanyilmaz,Mussie Birhane,Roy Fishwick,Carlos del Castillo 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.5
The construction industry plays a critical role in tackling the challenges of climate change, carbon emissions, and resource consumption. To achieve a low-emission built environment, urgent action is required to reduce the carbon emissions associated with steel production and construction processes. Reusing structural steel elements could make a significant impact in this direction, but there are five key challenges to overcome: limited material availability, maximizing different reusable materials from demolition, lack of adequate design rules and standards, high upfront costs and overlooked carbon impact of the demolition prior to construction, and the need to engage and coordinate the complete construction ecosystem. This article described these barriers and proposed solutions to them by leveraging the digital technologies and artificial intelligence. The proposed solutions aim to promote reuse practices, facilitate the development of certification and regulation for reuse, and minimize the environmental impact of steel construction. The solutions explored here can also be extended to other construction materials.
Enrique Rocha-Rangel,Juan López-Hernández,José A. Rodríguez-García,Eddie N. Armendáriz-Mireles,Carlos A. Calles-Arriaga,W. J. Pech-Rodríguez,José A. Castillo-Robles 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.8
In this work, strontium titanate samples were prepared starting from SrCO3 and TiO2 powders mixture. Raw materials wereactivated mechanically in a planetary mill and then calcined at different temperatures (900 to 1300 oC). Powders after grindingwere analyzed by differential thermal analysis in order to follow the carbonate decomposition. On the other hand, samplesresulting from heat treatment were characterized by XRD, SEM and electrical measurements. XRD analysis determines thatSrTiO3 synthetized presents the cubic structure of perovskite. Complete reaction for SrTiO3 compound formation occurs at1200 oC. SEM observations indicate the presence of a microstructure with very small gran size and consequently a largenumber of grain boundaries. Electrical measurements suggest the formation of a material with high insulating capacity. Withthis evidence, it can be concluded that solid state reactions activated mechanically, proved to be an effective way to fabricatestrontium titanate compound with very fine microstructure and high insulating behavior.
Jose I. Martínez-Quesada,Javier E. Anaya-Ayala,Santiago Mier y Terán-Ellis,Montserrat Miranda-Ramírez,Luis H. Arzola,Christopher Ruben-Castillo,Juan C. Aramburo,Jesus M. de los Ríos,Carlos A. Hinojosa 대한혈관외과학회 2022 Vascular Specialist International Vol.38 No.2
Chronic limb-threatening ischemia is rarely associated with previous traumatic injury. We present a case of a 28-year-old male with progressive digit ulcers, a weak pulse, cyanosis, and a cold limb. Eight months prior, he had a motorcycle accident resulting in a right clavicle fracture and brachial plexus injury. Computed tomography angiography revealed occlusion of the right subclavian artery near a surgically implanted reduction plate. The patient underwent an open subclavianbrachial bypass with a reversed saphenous vein graft. His postoperative recovery was uneventful. After 3 months, he had a euthermic right hand with a palpable pulse and his ulcers had completely healed. This case reinforces the need for patients with a neurological deficit in the upper extremity caused by blunt trauma to undergo thorough vascular examination to identify potential arterial injury and compromised perfusion.