Two-stage estimation algorithm based on interleaved OFDM for a cooperative bistatic ISAC scenario

This paper considers a cooperative bistatic scenario for integrated sensing and communication (ISAC) paradigm, where transmitter and receiver base stations (BS) are connected through the front-haul to a central unit (CU), enabling cooperation. A multiple-input multiple-output (MIMO) configuration is considered in combination with orthogonal frequency division multiplexing (OFDM). The communication and radio-sensing functions are performed in orthogonal sets of sub-carriers, where the sub-carriers allocated to radio-sensing are distributed among antennas in an interleaved way. The interleaved frame structure is exploited in the design of a new parameter estimation method. The proposed method is a two-stage algorithm to estimate the delay/Doppler shift and angular position of objects (paths) in the channel. First, the multiple signal classification (MUSIC) algorithm estimates the angle-of-arrival (AoA) of the paths. Then, the delay, Doppler shift and angle-of-departure (AoD) are jointly estimated for each AoA combining an extended search over the AoD domain and a two-dimensional periodogram. The simulations show that the delay, Doppler shift and AoA are estimated correctly, while the estimation of the AoD may report error, although it can be compensated.publishe

Quasi-orthogonal SFBC for monostatic MIMO ISAC scenarios

This paper studies the performance of the quasi-orthogonal Tirkkonen spatial-frequency block code (SFBC) for integrated sensing and communication (ISAC) scenarios. The considered scenario is a MIMO monostatic ISAC base station (BS), where transmitter and radar antenna arrays are co-located enabling the virtual array concept. The quasi-orthogonal Tirkkonen SFBC is encapsulated in an OFDM waveform, the radar processing is performed over the resulting OFDM frame. The performance in terms of radar and communication metrics of Tirkkonen SFBC is presented and compared with orthogonal Alamouti SFBC and the spectrally interleaved waveform approach, widely used in radar-like scenarios. The resulting Mean Square Error (MSE) of the Angle of Arrival (AoA) is chosen as the radar metric while the bit-error-rate (BER) is used to present the communication performance. The results show that Tirkkonen is a good candidate for future ISAC scenarios.publishe

Diseño de infraestructura vial para mejorar el servicio de transitabilidad Calabocillo – Naranjos tramo Km 0+000 - 05+917 provincia Cutervo-Cajamarca. Chiclayo. 2020

El presente estudio tiene como objetivo general diseñar la infraestructura vial para mejorar el servicio de transitabilidad Calabocillo – Naranjos tramo Km 0+000 - 05+917 provincia Cutervo-Cajamarca. Chiclayo. 2020. La investigación es de tipo aplicada, diseño no experimental, nivel descriptivo, enfoque cuantitativo, la población y la muestra está constituida por la longitud total de 5+917 km de la carretera, por ello se dice que tiene una muestra no probalistica y por conveniencia, la técnica para recoger datos fue la observación y en instrumento la ficha de observación o registro. Los resultados indicaron en cuanto a su topografía que era accidentada tipo 3 y un IMDa proyectado a 10 años de 356 veh/día, el suelo representativo de la zona es del tipo Arcilloso con materia inorgánica de baja o mediana plasticidad (CL). Su CBR es de 3.25% a 8.05%, los datos pluviométricos fueron obtenidos de la estación Cutervo, con los cuales se diseñaron 4 alcantarillas de ø= 0.70 m, un Baden trapezoidal y cuneta triangular de 5 917 m de longitud. Se obtuvo como conclusión general, el diseño geométrico para la carretera de tercera clase con una velocidad de diseño de 30 km/h basado en la normativa peruana DG – 2018 y el diseño de la estructura con afirmado basado en la metodología NAASRA (ver en diseños página 114)

Análisis de las fallas del muro de contención de la carrera 7 con calle 14 y 11 de Girardot, Cundinamarca.

Analizar el estado actual del muro de contención por gravedad ubicado en la carrera 7 entre calle 14 y 11 del municipio de Girardot/Cundinamarca, para determinar si presenta fallas en el concreto ciclópeo y así, plantear una posible solución.La presente investigación se realizó con el objetivo de analizar el estado actual del muro de contención por gravedad ubicado en la carrera 7 entre calle 14 y 11 del municipio de Girardot/Cundinamarca, para determinar si presenta fallas en el concreto ciclópeo y así, plantear una posible solución. Para ello se utilizó, el método que propone Antonio Aguado, apoyándose desde un enfoque cuantitativo, con un tipo de estudio no experimental- trasversal y el método es deductivo con alcance explicativo, el cual permite identificar las variables y contrastarlas, a partir de un estudio de suelos, levantamiento topográfico, posterior a eso modelación en 3D; un ensayo de laboratorio (esclerómetro) y un cálculo volumétrico. Los resultados obtenidos en el ensayo de esclerómetro mostraron que la estructura a pesar de ser de tan avanzada vetustez, su resistencia se ha mantenido a lo largo del tiempo, lo cual no representa un factor determinante en cuanto a falla en el concreto ciclópeo; considerando que fue construido aproximadamente hace 88 años. Por último, se pudo determinar que el sistema constructivo del muro de contención por gravedad cumple con las normas actuales y su estado es aceptable, pese que tiene una vetustez de más de 80 años. A su vez, el muro por su volumetría, peso y dimensiones cumplen con los factores de seguridad de muros de contención según la NSR- 10. Al igual, mantiene su geometría, conserva su resistencia según los ensayos realizados, debido que el concreto del muro tiene una resistencia de 210 MPa, lo cual cumple con los requerimientos de concreto simple. Según esta investigación el muro aún cumple con el objetivo inicial al que fue diseñado, como contenedor de tierras, pero se debe resaltar que el sistema de contención presenta algunas fallas estructurales que deben ser reparadas oportunamente para que no sean un problema eventualThe present investigation was carried out with the objective of analyzing the current state of the containment wall by gravity located in the 7th street between 14th and 11th streets of the municipality of Girardot / Cundinamarca, to determine if it presents faults in the concrete terrain and thus, to raise a possible solution. To this end, the method as proposed by Antonio Aguado, supported by a quantitative approach, with a non-experimental-cross-sectional type of study and the method is deductive with explanatory scope, which allows to identify the variables and contrast them, from a soil study, topographic survey, after that 3D modeling; a laboratory test (sclerometer) and a structural calculation. The results obtained in the sclerometer test showed that the structure, despite being of such advanced age, its resistance has been maintained over time, which does not represent a determining factor in terms of failure in the cyclopean concrete; considering that it was built approximately 88 years ago. Finally, it was possible to determine that the constructive system of the retaining wall by gravity complies with the current norms and its condition is acceptable, although it has an age of more than 80 years. In turn, the wall by its volume, weight and dimensions comply with the safety factors of retaining walls according to the NSR-10. Likewise, maintains its geometry, retains its strength according to the tests carried out, because the concrete of the wall It has a resistance of 210 MPa, which meets the requirements of simple concrete. According to this investigation, the wall still meets the initial objective to which it was designed, as a land container, but it should be noted that the containment system presents some structural faults that must be repaired in a timely manner so that they are not an eventual problem

Cooperative multiterminal radar and communication: a new paradigm for 6G mobile networks

The impending spectrum congestion imposed by the emergence of new bandwidth-thirsty applications may be mitigated by the integration of radar and classic communications functionalities in a common system. Furthermore, the merger of a sensing component into wireless communication networks has raised interest in recent years and it may become a compelling design objective for 6G. This article presents the evolution of the hitherto separate radar and communication systems towards their amalgam known as a joint radar and communication (RADCOM) system. Explicitly, we propose to integrate a radio sensing component into 6G. We consider an ultra-dense network (UDN) scenario relying on an active multistatic radar configuration and on cooperation between the access points across the entire coverage area. The technological trends required to reach a feasible integration, the applications anticipated and the open research challenges are identified, with an emphasis on high-accuracy network synchronization. The successful integration of these technologies would facilitate centimeter-level resolution, hence supporting compelling high-resolution applications for next-generation networks, such as robotic cars and industrial assembly lines.publishe

On SFBC schemes for enabling virtual array concept in monostatic ISAC scenarios

The integrated sensing and communication (ISAC) paradigm is being proposed for 6G as a new feature of the physical layer (PHY), for tackling dual-functional applications, i.e., demanding radio-sensing and communication functions, such as the Internet of Things (IoT) and autonomous driving systems. This work considers the integration of sensing and communications functionalities in a unique platform. To achieve this goal, the use of orthogonal space frequency block codes (SFBC) is proposed. SFBC code orthogonality enables both the separation of communications data streams at a user terminal and the estimation of target parameters. The SFBC enhances the communications link diversity without requiring channel state information knowledge at the transmitter and enable the virtual antenna array concept for enhancing the direction-finding resolution. The use of different SFBCs provides a tradeoff between achieved diversity and sensing resolution. For example, an Alamouti code, applicable for the case with two transmitting antennas, duplicates sensing resolution and achieves a diversity order of two while the use of a Tarokh code, applicable for a scenario with four transmitting antennas, provides a fourfold better resolution and diversity order of four. However, the code rate achieved with the Tarokh code is half of the one achieved with the Alamouti code. Furthermore, the unambiguous range is reduced since the bandwidth is divided to multiplex the different antenna signals. For its simplicity, good performance and reduced integration requirements, the method is promising for future ISAC systems.publishe

SIMULACIÓN DE LA INTERFERENCIA PROVOCADA POR UN SISTEMA SATELITAL GLOBALSTAR-LEO EN UNA ESTACIÓN TERRESTRE UTILIZANDO MATLAB (Original)

The aim of the present work was to simulate through the Matlab mathematical tool the behavior of the interferences caused by a satellite system in a ground station. For the investigation, the GlobalStar-LEO system of 48 satellites operating in the 11 GHz band was selected. Some parameters of the interfering satellites and the orbit were determined; average anomaly, eccentric anomaly, true anomaly, satellite movement, longitude and latitude, while for the calculation of the interference of each satellite on the fixed land system were determined; the angles of visibility, the ratio between the interfering signal and the level of noise in the receiver for each one of them. Obtained these parameters it was possible to simulate the probability density function of the GlobalStar system interference on the ground station. It is concluded that the mathematical model in conjunction with the software allows simulating the interference produced by a satellite system in low orbit.El objetivo del presente trabajo fue simular mediante la herramienta matemática Matlab el comportamiento de las interferencias provocadas por un sistema satelital en una estación terrestre. Para la investigación se seleccionó el sistema GlobalStar-LEO de 48 satélites operando en la banda de 11 GHz. Fueron determinados algunos parámetros de los satélites interferentes y la órbita; anomalía media, anomalía excéntrica, anomalía verdadera, movimiento satelital, longitud y latitud, mientras que para el cálculo de la interferencia de cada satélite sobre el sistema fijo terrestre se determinaron; los ángulos de visibilidad, la razón entre la señal interferente y el nivel de ruido en el receptor para cada uno de los mismos. Obtenidos estos parámetros fue posible simular la función densidad de probabilidad de la interferencia del sistema GlobalStar sobre la estación terrestre. Se concluye que el modelo matemático en conjunto con el software permite realizar la simulación de la interferencia producida por un sistema satelital de órbita baja

Nuevos registros y extensiones de distribución de reptiles (reptilía: squamata) para el estado de Zacatecas, México

Two new records of reptiles for Zacatecas are given, Sceloporus parvus and Lampropeltis alterna, also a distribution extension for Salvadora grahamiae lineata. These records confirm the presence of S. parvus and S. grahamiae lineata in the Mexican high  plateau, whereas for L. alterna the known distribution extends to the southern limit for the known distribution limit. This records increase to 67 the number of species recorded in the state. Se proporcionan dos nuevos registros de reptiles para Zacatecas; Sceloporus parvus y Lampropeltis alterna así como una extensión de distribución correspondiente a Salvadora grahamiae lineata. Estos registros confirman plenamente la presencia de S. parvus y S. grahamiae lineata en el interior del Altiplano Mexicano, en tanto  que para L. alterna se extiende notoriamente el límite sur de la distribución conocida para la especie. Estos  registros incrementan a 67 las especies de reptiles reportados para la entidad

Los efectos de la regulación de tarifas de agua y saneamiento sobre la eficiencia de las empresas prestadoras de servicios de saneamiento

La prestación del servicio de agua y saneamiento suele estar regulado por entidades reguladoras que establecen, entre otros mecanismos, la tarifa que permita a las empresas brindar un servicio sostenible, eficiente y equitativo. En ese contexto, el objetivo del presente trabajo de investigación consiste en tratar de entender las ventajas de ciertas metodologías de regulación tarifaria en relación con la eficiencia de las empresas. Para ello, se presenta un marco teórico que expone cada uno de los modelos y las distintas aristas sobre las cuales se evalúan. Posteriormente, se ilustra la casuística encontrada sobre la aplicación de estas metodologías sobre la eficiencia de las empresas. La revisión de literatura realizada a partir de casos en América y Europa presenta evidencia mixta que no permite concluir — con total certeza— que exista una metodología de regulación tarifaria que promueva más la eficiencia y calidad del servicio en comparación a otras. Los estudios demuestran que existen otros criterios, más allá de la metodología de regulación tarifaria, que explican los resultados positivos o negativos de la eficiencia de las empresas del sector como la normativa regulatoria, la propiedad, la información disponible, la situación de la empresa en el tiempo de la evaluación y la metodología de estimación de la productividad.The provision of water and sewage services is typically regulated by regulatory entities that establish, among other mechanisms, methods of regulation to allow companies to provide a sustainable, efficient and equitable service. In that context, the aim of this research work is to try to understand the advantages of certain methods of regulation in relation to the efficiency of companies. To do this, a theorical framework is presented that exposes each of the models and the different aspects on which they are evaluated. Subsequently, we illustrate case studies in America and Europe on the application of these methods on the efficiency of companies. The literature review carried out presents mixed evidence that does not allow us to conclude, with certainty, that there is a method of regulation that promotes efficiency and service quality more than others. The studies show that there are other criteria, beyond methods of regulation, that explain the positive or negative results of the sector companies’ efficiency such as regulatory legislation, ownership, available information, the company’s situation at the time of evaluation, and the productivity estimation methodology

Enhanced Seismic Structural Reliability on Reinforced Concrete Buildings by Using Buckling Restrained Braces

The control of vibrations and damage in traditional reinforced concrete (RC) buildings under earthquakes is a difficult task. It requires the use of innovative devices to enhance the seismic behavior of concrete buildings. In this paper, we design RC buildings with buckling restrained braces (BRBs) to achieve this objective. For this aim, three traditional RC framed structures with 3, 6, and 9 story levels are designed by using the well-known technique nondominated sorting genetic algorithm (NSGA-II) in order to reduce the cost and maximize the seismic performance. Then, equivalent RC buildings are designed but including buckling restrained braces. Both structural systems are subjected to several narrow-band ground motions recorded at soft soil sites of Mexico City scaled at different levels of intensities in terms of the spectral acceleration at first mode of vibration of the structure Sa(T1). Then, incremental dynamic analysis, seismic fragility, and structural reliability in terms of the maximum interstory drift are computed for all the buildings. For the three selected structures and the equivalent models with BRBs, it is concluded that the annual rate of exceedance is considerably reduced when BRBs are incorporated. For this reason, the structural reliability of the RC buildings with BRBs has a better behavior in comparison with the traditional reinforced concrete buildings. The use of BRBs is a good option to improve strength and seismic behavior and hence the structural reliability of RC buildings subjected to strong earthquake ground motions