Attitude Determination & Control System Design and Implementation for a 6U CubeSat Proximity Operations Mission

The purpose of this work is to discuss the attitude determination and control system (ADCS) design process and implementation for a 12 kg, 6U (36.6 cm x 23.9 cm x 27.97 cm) CubeSat class nano-satellite. The design is based on the requirements and capabilities of the Application for Resident Space Object Proximity Analysis and IMAging (ARAPAIMA) proximity operations mission. The satellite is equipped with a cold gas propulsion system capable of exerting 2.5 mN m torques in both directions about each body axis. The attitude sensors include an angular rate gyro and star tracker (STR), supplemented by the payload optical array cameras. The dynamic simulation of the satellite includes extensive environmental models and analyses that show how the satellite attitude is affected by aerodynamic drag, solar radiation pressure, gravity gradient torques, and residual magnetic moments. A mechanical propellant slosh model and a reaction torque analysis of the deployable solar panel hinges approximate the internal dynamics of the satellite. A trade study is presented to justify the use of a reaction control thruster actuated system over the more traditional reaction wheel configuration. Both actuation systems are modeled to hardware specifications and their propellant and energy requirements are examined alongside pointing performance. Two methods of accounting for sensor noise and sampling rates are presented. The first is an extended Kalman filter based on the nonlinear model of a rate gyro coupled with quaternion attitude kinematics. The second presents a gyro-less angular rate observer capable of extrapolating STR measurements to the desired frequency. An additional method uses images from the payload cameras to perform [camera] frame centering maneuvers and to address the possibility of bias in the controller reference signal. Four different controllers are described to reflect the chronological progression of the ADCS design. The first controller, designed to perform long angle maneuvers and target tracking, utilizes fixed gain eigenaxis control. The same controller is then augmented with a parallel proportional-integral-derivative (PID) type control law using scheduled gains. This configuration is designed to switch between eigenaxis and PID control during imaging procedures to take advantage of the integral control introduced by the PID algorithm. To reduce system complexity, a modified eigenaxis control law, which incorporates scheduled integral control but does not require a switch to PID control, is introduced. A discrete time equivalent of the modified eigenaxis control law is also developed. Additionally, a brief description of a detumbling control law is presented. Each of the four control laws is paired and tested with the different feedback and estimation methods discussed. An extensive showcase of numerical simulation results outlines the pointing performance of each system configuration and evaluates their capabilities of meeting a 1 arcmin pointing requirement. A comparison of the different properties and performance of each control system configuration precedes the selection of the discrete modified eigenaxis control law as the best alternative

Spacecraft Trajectory Planning for Optimal Observability using Angles-Only Navigation

This work leverages existing techniques in angles-only navigation to develop optimal range observability maneuvers and trajectory planning methods for spacecraft under constrained relative motion. The resulting contribution is a guidance method for impulsive rendezvous and proximity operations valid for elliptic orbits of arbitrary eccentricity. The system dynamics describe the relative motion of an arbitrary number of maneuvering (chaser) spacecraft about a single non-cooperative resident-space-object (RSO). The chaser spacecraft motion is constrained in terms of the 1) collision bounds of the RSO, 2) maximum fuel usage, 3) eclipse avoidance, and 4) optical sensor field of view restrictions. When more than one chaser is present, additional constraints include 1) collision avoidance between formation members, and 2) formation longevity via fuel usage balancing. Depending on the type of planetary orbit, quasi-circular or elliptic, the relative motion dynamics are approximated using a linear time-invariant or a linear time-varying system, respectively. The proposed method uses two distinct parameterizations corresponding to each system type to reduce the optimization problem from 12 to 2 variables in Cartesian space, thus simplifying an otherwise intractable optimization problem

Plan de viabilidad para la creación de una academia musical en San Cristóbal de La Laguna

La música se trata de un lenguaje universal que ha acompañado a la sociedad durante un proceso de evolución (Díaz, 2018). Aunque tradicionalmente la enseñanza musical iba dirigida a los pequeños de la casa, se ha observado un aumento de interés por parte de los mayores, es por ello que se ve de gran interés ofrecer este servicio a un público más amplio. Además de esto, es necesario abrir el campo de mira e innovar más allá del concepto tradicional de academia musical, incorporando nuevos géneros y propuestas adaptadas a los gustos actuales. Este trabajo tiene como finalidad la creación de una academia musical con estas características de integración e innovación, bautizada como Academia Musical Allegro, situada en San Cristóbal de La Laguna.Music is a universal language that has accompanied society during a process of evolution (Díaz, 2018). Although musical education was traditionally aimed at the little ones in the house, an increase in interest has been observed on the part of the elderly, which is why it is of great interest to offer this service to a broader public. In addition to this, it is necessary to open the field of vision and innovate beyond the traditional concept of a musical academy, incorporating new genres and proposals adapted to current tastes. The purpose of this work has been doing for create a musical academy with these characteristics of integration and innovation, called as Allegro Musical Academy, located in San Cristóbal de La Laguna

Combined extended FIR/Kalman filtering for indoor robot localization via triangulation

A combined unbiased finite impulse response (UFIR) and Kalman filtering algorithm is proposed for mobile robot localization via triangulation utilizing noisy measurements. We consider a mobile robot travelling on an indoor floorspace with three nodes in a view. Under the not well-known initial robot state and noise statistics, the extended Kalman filter (EKF) may produce unacceptable estimates. The iterative extended UFIR (EFIR) filter ignores the noise statistics, but requires N initial points of linear measurements which are unavailable. The combined EFIR/Kalman algorithm utilizes N first EKF estimates with approximately set initial conditions and noise statistics as linear measurements for EFIR filter. It is shown that the combined algorithm is more accurate than EKF in robot localization under the real operation conditions. Simulations are provided for piecewise and circular robot trajectories

Repercusiones financieras por la ausencia, la aplicación incorrecta o la no aplicación de las políticas de control interno en pequeñas empresas del giro industrial en la ciudad de Puebla

"En las empresas, el control interno es una herramienta muy importante para salvaguardar los bienes de un ente económico en cualquiera de sus tamaños y de sus giros, así mismo es fundamental el verificar la exactitud y confiabilidad de la información financiera, por lo que el presente trabajo tiene como objetivo identificar la repercusión financiera que tienen las pequeñas empresas del giro industrial en la ciudad de Puebla por la ausencia, la aplicación incorrecta o la no aplicación de las políticas de control interno que apoyen a la minimización de gastos y/o costos adicionales o extraordinarios en las empresas. Metodológicamente se aborda bajo el método mixto deductivo-inductivo considerando una muestra de 48 pequeñas empresas del giro industrial de la ciudad de Puebla, en las que se aplicó un cuestionario a los contadores, administradores y/o encargados de la administración de estas. Los resultados muestran las repercusiones financieras negativas que tienen las pequeñas empresas del giro industrial en la ciudad de Puebla por la ausencia, la aplicación incorrecta o la no aplicación de las políticas de control interno para aportar una posible solución para evitar costos y/o gastos adicionales se propone la implementación de formatos que regulen áreas funcionales de la organización"

Borden Parker Bowne's treatment of the problem of change and identity

Thesis (Ph.D.)--Boston University N.B.: between p. 149 and p. 159, there are only five pages without numbers. It appears that the author mis-numbered the pages; no actual content is missing.The problem of this dissertation is that of the relations of change and identity with special reference to its treatment in the philosophical writings of Borden Parker Bowne. The historical backgrounds of the problem are investigated in order to shed light on Bowne's views. The problem of change and identity is one of the most difficult and persistent as well as one of the most ancient problems of thought. Traces of it may be found in history as far back as early Indian philosophy. The Rg Veda (about 1500-1000 B.C.), which is one of the most ancient monuments of civilization that we possess, develops a cosmic pantheism according to which a persistent unitary being manifests itself through the numberless forms of our changing world. In the subsequent philosophies of the Brahmanas, Upanishads, and later Hindu and Sanskrit literatures, the crudity of this primitive view is attenuated, but pantheism ,continues to be the characteristic note. The concepts of Brahma and Atman, as universal and individual realities respectively, are important developments in : the evolution of the problem in the second period of Indian philosophy (1000-500 B.C.). In the third period, that of the Hindu and Sanskrit literatures of Vedanta, Vaiseshika, Nyaya, Sankya, Yoga, Mimansa, (from 500 B. C. on), the problem shifts from cosmology to psychology, from the objective world to the world of mind. Two concepts are specially significant during this period, namely, that of Manas Inferior, the changing mind; and that of Manas Superior, the unchanging soul. The problem of change and identity is also treated in the Chinese philosophy, especially in the Tao Teh King of Lao-Tze, with its theory of Reason as a metaphysical ultimate, in which "the ten thousand things" find explanation and justification. Lao-Tze also anticipates the theory of "Opposites" that is to appear later on in Greek philosophy. Not until the Greek pre-Socratics, however, do we find the problem methodically treated. We may even say that the fundamental theme of Greek Pre-Socratic Philosophy, is that of change and identity. The Milesians, the Eleatics, Empedocles, Heraclitus, Anaxagoras, Democritus, Pythagoras all aimed at the same problem through the same question :-What is the one root and trunk of the tree whose branches constitute the many phenomena of the world? Socrates contributes to the clarification of the issue with his view of the logical importance of the Concept. Plato enriches thought about the problem of identity with his Ideas, and Aristotle gives it final form for the Greek period by distinguishing between logical identity, metaphysical identity, and identity as object of the intellect. After Aristotle, the Scholastics spoke of Substance as the only true being, the only unchanging reality. Locke and Hume referred to it as the "unknown cause" of impressions not originated in the senses. Berkeley identified it with Mind. Descartes spoke of matter as extended substance, of mind as unextended substance, and of God as the fundamental underlying substance that connects matter and mind. Spinoza identified substance with nature, and nature he called God. In him, therefore, the principle of identity is nature itself. Leibniz, however, is to be credited with a major contribution. He made reality to consist of individual monads, varying in degrees of self-consciousness, self-direction, and ability to realize themselves. Identity, therefore, he identified with Being itself, but Being he identified with activity. Kant's position with respect to the problem in question is rather problematic because of his so-called Dinge an sich and all the ambiguities of his Categories. But it can at least be said that for Kant identity is one of the functions of the mind. Mind imposes it upon its world of phenomena. Schelling does away with Kant's noumena, and speaks of the Absolute, as the organic whole, in which all theses and antitheses find ultimate explanation. Identity, for him, is a function of the Absolute. Hegel makes this Absolute an organic dialectical whole, objective cosmic spirit. Identity for Schopenhauer is of the nature of the universal will-to-be. This is the metaphysical ultimate in which he finds all continuity. Hermann Lotze (1817-1881) goesbeyond previous thinkersinhisanalysis of change and identity. For him, the problem finds solution only on the plane of personality. Only persons change while remaining identical. Change and identity taken abstractly are logical contradictories. In personal experience they find exemplification and explanation. Borden Parker Bowne, student of Lotze, owes much to his teacher in the position he occupies with respect to the problem of change and identity, but does not depend completely on the line of argument laid out by Lotze. Bowne (1847- 1910) treats the problem of change and identity from the points of view of psychology, logic, epistemology, metaphysics, and religious and social thought. The main steps of his argument in psychology run as follows: The reality of the self is a primary condition of the mental life. Sensations require an organizing agent and consciousness is the agent. The essence of self is memory, and the essence of memory is recognition. Recognition is impossible if the recognizing agent is not identical with itself. In his argument from the point of view of logic, stress is laid on identity as the fundamental function of all faculties, on the unity of the mental subject, and on the necessity of this unity for all inference, memory, and knowledge. Mind is the coordinator of the one and the manifold; and the notion is its shorthand expression for the many. From the point of view of epistemology, attention is called to the mind as active and constitutive in sensation, for mind is the relational principle. Apart from this principle experience is impossible. Recurrence of experience itself is possible only to a universalizing intelligence. The problem of change and identity belongs especially in the field of metaphysics. Bowne's argument in this field begins by way of definitions and penetrating analyses of the terms of change and identity and their corresponding implications. The two terms taken abstractly contradict each other. Identity and change are concretely found only in consciousness. Hence, personality, the common ground of both, is the only solution to the problem. Unity is ultimate. "The heavens are crystallized' mathematics," and nature is a thought world. Knowledge of nature implies mind at both ends, the knower and the known. The universe is a "logical togetherness." Bowne applies the metaphysics of change and identity to the daily experiences of the social process. The progressive element in society is the factor of change; the conservative, the factor of identity. Bowne's position is that of a social organism, where change is stimulated through discussion and criticism as instruments of progress, and permanence is stimulated through the spiritual growth of the church as conserver of value achieved. The following problems and observations are some of the results of our investigation. (1) Like Herbart, Bowne (for pedagogical reasons) starts with "concepts" already given to us in experience. He taught his students by pointing out the contradictions implied in such concepts. But it is not necessarily true that this method is the most pedagogical. (2) Bowne's metaphysics of change and identity has undergone numerous changes of special interest during his revisions of his works. In 1882 Bowne published his Metaphysics. In 1898 it was revised. The revised Metaphysics lays more emphasis on logic than does the original edition of 1882, and stresses more the element of identity than the element of change. The author is also more careful of the connotation of his words. A benign attitude is observed in the revised edition toward Heraclitus, as over against the unfavorable previous treatment that he received in the first edition. (3) Throughout the treatment of the problem of change and identity, Bowne is not consistent in naming his principle of permanence. Sometimes it is called intelligence, sometimes, soul. At times, it is given the name of substance. At other times he calls it monad; but he also calls it ego, and self. (4) Up to 1897 Bowne seems to have limited the term experience to physical sensations as we may infer from his discussion of apriorism and empiricism; but afterwards, experience comes to mean for Bowne all the data of self-consciousness, as we may infer from his discussion of the Kantian categories. (5) Bowne is not consistent in his theory of soul; neither is he consistent in his attitude towards logic. He attacks logic as a discipline, but expects from it more than any other philosopher naturally would. In method of exposition he himself is a most rigorous logician. (6) In his social theory, there are also apparent contradictions, at least between his atomistic individualism and his organic pluralism. (7) The most important problem in the metaphysics of Bowne, however, is his metaphysics of time. For him, "God is timeless and changeless." But in several passages, Bowne tells us that "Change is a fact in reality itself," that "the divine activity is temporal," and "Time is eternally coexistent with God." It appears impossible to reconcile Bowne's contradictory views on time. How can thought reconcile the timelessness of God with the activity of God? If personality is the essential metaphysical ultimate, time must be metaphysically real. A serious problem remains unsolved in this investigation, namely, the respect in which the self in Bowne explains the problem of change and identity. Is it because the self as such is permanent and unchanging, or because it experiences both the changing and the permanent? Of course, if the latter be the case, change and identity are fundamental characteristics of the self; but in the case of Bowne, we can neither affirm the later nor the former, in view of the fact that Bowne's theories of the soul are obscure and contradictory

Impacto de las obras públicas y privadas sobre la estructura urbana en la Ciudad de Santiago de los Caballeros: 1970-2020

La falta de planificación que ha imperado en ciudades dominicanas obedecía a una política “laissez- faire” regida por agentes sociales disgregados y traducido en un uso del espacio urbano incongruente, ilógico y desorganizado como resultado de múltiples obras puntuales desarrolladas por entidades independientes con visiones variadas. La transformación multisectorial del territorio rural o natural en área urbana como proceso intenso, continuo y evolutivo afecta directamente al paisaje modificando la habitabilidad, vulnerabilidad y satisfacción de sus habitantes, y repercute en la calidad de vida. La actual dinámica urbana de Santiago se ve reflejada en un sostenido crecimiento espacial generado por procesos de urbanización acelerados, que incorpora, nuevos suelos urbanos al mercado de tierras. Esta investigación valora la incidencia de intervenciones constructivas públicas y privadas en la estructura urbana, relacionada con normativas, servicios de infraestructura y agentes involucrados en toma de decisiones. Se limita al período comprendido entre años 1970 al 2000, considerando éste como el de mayor crecimiento urbano del siglo XX. Para entender esta dinámica, se estudia el desarrollo urbano con las transformaciones ambientales, económicas, socio- políticas, y uso de suelo, basado en informaciones disponibles en organismos correspondientes y entrevistas a expertos en la problemática.The lack of planning that has prevailed in Dominican cities was due to a “laissez-faire” policy governed by disintegrated social agents and translated into an incongruous, illogical and disorganized use of urban space as a result of multiple specific works developed by independent entities with varied visions. The multisectoral transformation of the rural or natural territory in an urban area as an intense, continuous and evolutionary process directly affects the landscape, modifying the habitability, vulnerability and satisfaction of its inhabitants, and affects the quality of life. The current urban dynamics of Santiago is reflected in a sustained spatial growth generated by accelerated urbanization processes, which incorporates new urban land to the land market. This research assesses the incidence of public and private constructive interventions in the urban structure, related to regulations, infrastructure services and agents involved in decision- making. It is limited to the period from 1970 to 2000, considering this as the one with the highest urban growth of the 20th century. To understand this dynamic, urban development with environmental, economic, socio-political, and land use transformations is studied, based on information available from corresponding agencies and interviews with experts on the problem

Estructura, función y jerarquía de actores en la cadena aloe en el estado falcón, Venezuela.

Actors who participate in the aloe production chain have centeredon development and producer training for the agronomicmanagement of the crop, production of by-products, and theadvancement of new organizational structures. However, littleis known about their structure, function and hierarchy. In thissense, the concept of social capital arises, which as a recent notionis located in the conceptual plane of relations and social systems.It is alternately a resource and a way to access resources, andtherefore, it is transformed into an important tool in the lifestrategy of individuals, by allowing them access to other resources,fostering their participation in organizations, and promotingcourses of action directed at improving their level of socialinclusion. Within this context, an actors’ map was built for thealoe production chain in the state of Falcón, Venezuela, with thepurpose of identifying all the entities interested in planning, designand performance evaluation in this chain. The methodologicalstrategy was sustained on the analysis of networks, with the aimof identifying, describing and analyzing relations establishedby agents in the chain. Results indicate that organizations withactions and direct responsibility in the chain present a structuraland functional dimension with minimal conditions to promote andsupport its competitive and efficient development, although it may be necessary to decrease administrative procedures. Likewise, wehighlight the participation of the Regional Executive as governingorgan, of producers as central agents of the process, and thelow valuation given to communication between agents, whichcan be transformed into a significant limitation for a competitiveperformance of activities to be undertaken. It is necessary, then,to bring forward efforts to unify criteria and joint visions tostrengthen the chain.Los actores participantes en la cadena aloe se han centrado en eldesarrollo y capacitación de productores en el manejo agronómicodel cultivo, producción de derivados y el adelanto de nuevas estructurasorganizativas. Sin embargo, poco se conoce acerca de suestructura, función y jerarquía. En este sentido, surge el conceptode capital social, el cual como noción reciente se ubica en el planoconceptual de las relaciones y los sistemas sociales. Es alternativamenteun recurso y una vía para acceder a recursos, por tantose transforma en una herramienta importante en la estrategia devida de los individuos, al permitirle el acceso a otros recursos,fomentar su participación en organizaciones y promover cursosde acción orientados a mejorar su nivel de inclusión social. Dentrode este contexto se construyó el mapa de actores de la cadena aloeen el estado Falcón, Venezuela, con el propósito de identificartodos aquellos entes interesados en la planificación, diseño y evaluacióndel desempeño de dicha cadena. La estrategia metódica sesustentó en el análisis de redes a los fines de identificar, describiry analizar las relaciones establecidas por los agentes de la cadena.Los resultados evidencian que los organismos con actuación yresponsabilidad directa en la cadena, presentan una dimensiónestructural y funcional con las condiciones mínimas para promovery apoyar su desarrollo competitivo y eficiente, aunque tal vezsea necesario disminuir los trámites administrativos. Asimismose destaca la participación del Ejecutivo Regional como órgano rector, de los productores como agentes centrales del proceso y labaja valoración otorgada a la comunicación entre agentes, lo cualllega a transformarse en una limitante significativa para un desempeñocompetitivo de las actividades a emprender. Es necesarioentonces adelantar esfuerzos en pro de unificar criterios y visionesconjuntas para fortalecer la cadena