Hacia un análisis cuantitativo de la Ciudad Informal: una aproximación desde la Habitabilidad Básica y la experiencia en Makeni (Sierra Leona)

La importantísima expansión urbana que sufren las principales ciudades de los países en vías de desarrollo, es el mayor reto que afronta la habitabilidad a nivel mundial. Dentro de la teoría general de la Habitabilidad Básica (HaB-ETSAM-UPM, 1995) la ordenación del territorio y el planeamiento urbanístico son las herramientas determinantes para orientar coherentemente los procesos de urbanización, como se reconoce también desde las principales esferas técnicas a nivel internacional. Pero tales herramientas deben enfocarse a una construcción eficiente del territorio, actuando desde una aproximación multidisciplinar, flexible y directa, que incida en las prioridades específicas de cada contexto. Para ello, resulta fundamental comprender a fondo las realidades específicas de estos ámbitos. La ciudad es un fenómeno complejo en esencia. El tejido construido, en constante proceso de cambio, es el caparazón visible que alberga una maravillosa mezcla entrelazada de espacios, funciones, flujos, personas.... Cada ciudad, diferente y única, se integra en su medio, se adapta a geografías, contextos y climas distintos, evoluciona según dinámicas propias, en incomprensibles (o casi) procesos evolutivos. El estudio de la ciudad, supone siempre una simplificación de la misma. La realidad urbana, por detallado que sea nuestro análisis, siempre contendrá indescifrables relaciones que se nos escapan. En cambio, necesitamos de métodos analíticos que nos ayuden a comprender algo esa complejidad. Acercarnos en ese análisis, es un paso previo fundamental para la formulación de respuestas. En este plano, de avance en la comprensión del hecho urbano, se sitúa este trabajo. Se pone el acento en el enfoque cuantitativo, profundizando en datos básicos concretos, siempre aceptando de partida que esta información es una componente mínima, pero esperamos que sustantiva, de un fenómeno inabordable. Y es esta búsqueda de comprensión material y cuantitativa de la ciudad, el objetivo esencial de la investigación. Se pretende proporcionar una base detallada de aquéllos aspectos fundamentales, que pueden ser medidos en los entornos urbanos y que nos proporcionan información útil para el diagnóstico y las propuestas. Para ello, se aportan rangos y referencias deseables, a través de una herramienta para la comprensión y la valoración de cada contexto, la Matriz de Indicadores. Esta herramienta se concibe desde la reflexión a la aplicación práctica, a la utilidad directa, al aporte concreto para quien pueda servir. Ésta es la voluntad decidida con la que se aborda este trabajo, centrado en los entornos urbanos donde el aporte técnico es prioritario: la Ciudad Informal. La Ciudad Informal, entendida aquí como aquélla que se desarrolla sin los medios suficientes (técnicos, económicos e institucionales) que proporciona la planificación, aquélla por donde la habitabilidad precaria se extiende. Es la ciudad que predomina en los países en vías de desarrollo, en los contextos de bajos recursos, allí donde, precisamente, se concentran los principales déficits y necesidades a nivel global. El enfoque nace de la teoría de la Habitabilidad Básica, de la definición de mínimos posibles para, desde allí, construir el espacio necesario para el desarrollo humano. Éste es el ámbito genérico objeto del trabajo que, a su vez, se nutre, de forma muy importante, de la experiencia directa en la ciudad de Makeni, en Sierra Leona. Esta ciudad nos sirve de prototipo experimental en un doble sentido. Por un lado, sirve como espacio empírico en el que chequear la metodología de valoración cuantitativa; y, por otro, el conocimiento de esta ciudad de tamaño medio africana, que se ha ido adquiriendo en los últimos cinco años, es una base directa para el desarrollo teórico de la propia metodología, que ayuda a atisbar lo esencial en contextos similares. El encaje de todo este recorrido se ha articulado desde una experiencia académica que, como docente, he coordinado directa e intensamente. Experiencia muy enriquecedora, que ha sumado muchas manos y mucho aprendizaje en este tiempo. Teoría y práctica en planeamiento urbano se alternan en el trabajo, nutriéndose la una de la otra y a la inversa. Trabajo que nace desde la pasión por la ciudad y el urbanismo. Desde la búsqueda por comprender y desde la vocación de actuar, de intentar mejorar y hacer más habitables los entornos urbanos. Especialmente allí donde las dificultades se agolpan y el camino se alarga, se llena de polvo. Acumular preguntas a cada paso. Cada vez más preguntas. Las respuestas, si existen, aparecen entrelazadas en dinámicas indescifrables de las que queremos formar parte. Fundirnos por momentos en la misma búsqueda, acompañarla. Sentirnos cerca de quiénes comienzan de cero casi cada día. Y otra vez, arrancar. Y compartir, desde el conocimiento, si acaso es que se puede. Y la ciudad. Brutal, imponente, asfixiante, maravillosa, imposible. Creación colectiva insuperable, de energías sumadas que se cosen sin patrón aparente. O sin más razón que la del propio pulso de la vida. Así se siente Makeni. ABSTRACT The important urban growth suffering major cities of developing countries, is the biggest challenge facing the global habitability. Within the general theory of Basic Habitability (HAB-ETSAM-UPM, 1995) spatial planning and urban planning are the crucial tools to consistently guide the urbanization process, as also recognized from the main technical areas worldwide. But such tools should focus on an efficient construction of the territory, working from a multidisciplinary, flexible and direct approach, that affects the specific priorities of each context. To do this, it is essential to thoroughly understand the specific realities of these areas. The city is essentially a complex phenomenon. The urban fabric in constant flux, is the visible shell that houses a wonderful mixture interlocking spaces, functions, flows, people.... Every city, different and unique, is integrated into its environment, adapted to geographies, contexts and climates, it evolves according to its own dynamics, along (almost) incomprehensible evolutionary processes. The study of the city, is always a simplification of it. The urban reality, even studied from a detailed analysis, always contain undecipherable relationships that escape us. Instead, we need analytical methods that help us understand something that complexity. Moving forward in this analysis is an essential first step in formulating responses. At this level, progressing in understand the urban reality, is where this work is located. The emphasis on the quantitative approach is placed, delving into specific basic data, starting always accepting that this information is just a minimal component, but we hope that substantive, of an intractable phenomenon. And it is this search for materials and quantitative understanding of the city, the main objective of the research. It is intended to provide a detailed basis of those fundamental aspects that can be measured in urban environments that provide us useful information for the diagnosis and proposals. To do this, desirable ranges and references are provided, through a tool for understanding and appreciation of each context, the Indicator Matrix. This tool is conceived from reflection to practical application, to a direct utility, concrete contribution to who can serve. This is the firm resolve with which this work is addressed, centered in urban environments where the technical contribution is a priority: the Informal City. The Informal City, understood here as the urban areas developed without the sufficient resources (technical, economic and institutional) which planning provides, where it is extended the precarious habitability. It is the city that prevails in developing countries, in low-resource settings, where, precisely, the main gaps and needs in the global context are concentrated. The approach stems from the theory of Basic Habitability, the definition of possible minimum, to build the necessary space for human development. This is the generic scope of the work object, that is also based in the direct experience in the town of Makeni, Sierra Leone. This city serves as an experimental prototype in two ways. On the one hand, it serves as a space where empirically check the quantitative assessment methodology; and, secondly, the knowledge of this African city of medium size, which has been acquired in the last five years, is a direct basis for the theoretical development of the methodology itself, which helps to glimpse the essence in similar contexts. The engagement of this whole journey has been articulated from an academic experience, directly and intensely coordinated as teacher. Enriching experience that has added many hands and much learning at this time. Theory and practice in urban planning are mixed at work, enriching the one of the other and vice versa. Work is born from the passion for the city and urbanism. From the search for understanding and from the vocation of acting, trying to improve and make more livable urban environments. Especially where the difficulties are crowded and the road is so long, full of dust. To accumulate questions at every turn. More and more questions. The answers, if do exist, appears inside indecipherable dynamics in which we want to be involved. Merge at times in the same search. Feel close to those who start from scratch almost every day. And again, move forward. And share, from knowledge, if possible. And the city. Brutal, impressive, suffocating, wonderful, impossible. Unsurpassed collective creation, combined energy mix that are sewn with no apparent pattern. Or for no reason other than the pulse of life itself. As it feels the city of Makeni

Cooperación universitaria para el desarrollo en Makeni (Sierra Leona)

Las ciudades medias africanas de menos de 500.000 habitantes representan el principal desafío urbano del momento a nivel mundial. Su desarrollo implicará, en las próximas décadas, un notable incremento de suelo urbano en los países en vías de desarrollo. La falta de recursos, de un marco normativo adecuado, de profesionales en planificación urbana y los déficits de habitabilidad ya existentes en estos entornos, son realidades que evidencian, entre otras, la urgencia de articular un importante esfuerzo colectivo. El planeamiento urbano y territorial convencional no es capaz de responder a estos retos en tiempo y escala. Por una parte, por la velocidad vertiginosa de la progresiva toma de tierra y el incesante crecimiento de la población y, por otra, debido a la dificultad que supone para la población asumir propuestas de planificación con visos de futuro en contextos en los que no existe cultura en planeamiento. Así, entre Madrid (España) y Makeni (Sierra Leona) surge una experiencia en la que la Universidad y la Cooperación al Desarrollo emergen como elementos críticos de fortalecimiento institucional y formativo. La colaboración entre universidades (uspceu-unimak) es el germen de un proceso de reflexión urbana que implica decididamente al Ayuntamiento y a los principales actores locales de la ciudad.Les ciutats mitjanes africanes de menys de 500.000 habitants representen el principal desafiament urbà del moment a nivell mundial. El seu desenvolupament implicarà, en les pròximes dècades, un notable increment de sòl urbà en els països en vies de desenvolupament. La manca de recursos, d’un marc normatiu adequat, de professionals en planificació urbana i els dèficits d’habitabilitat ja existents en aquests entorns, són realitats que evidencien, entre altres, la urgència d’articular un important esforç col·lectiu. El planejament urbà i territorial convencional no és capaç de respondre a aquests reptes en temps i escala. D’una banda, per la velocitat vertiginosa de la progressiva presa de terra i l’incessant creixement de la població i, de l’altra, a causa de la dificultat que suposa per a la població assumir propostes de planificació amb aspectes de futur en contextos en què no hi cultura en planejament. Així, entre Madrid (Espanya) i Makeni (Sierra Leone) sorgeix una experiència en la qual la Universitat i la Cooperació al Desenvolupament emergeixen com a elements crítics d’enfortiment institucional i formatiu. La col·laboració entre universitats (uspeceu-unimak) és el germen d’un procés de reflexió urbana que implica decididament l’Ajuntament i als principals actors locals de la ciutat.Medium-sized african cities, with fewer than 500,000 inhabitants are the main urban challenge of the moment. In the coming decades,urban development will involve a significant increase in urban land in developing countries. The lack of resources, an appropriate regulatory framework, professionals in urban planning and habitability in urban environments of these cities, are realities that show the urgency for to articulate a major collective effort. Conventional urban and regional planning is not able to respond to these challenges in time and scale. On the one hand because of the speed of the progressive increase of illegal settlements and the constant population growth. On the other hand on account of the difficulty for people to take proposals forward planning in contexts where there is no culture in planning. Between Madrid (Spain) and Makeni (Sierra Leone) starts an experience in which the University and Development Cooperation emerge as critical elements of institutional and educational strengthening and training. Collaboration between universities (uspceu-unimak) is the beginning of a process of urban reflection involving the City Council and local stakeholders

Optimal Location and Sizing of PV Generation Units in Electrical Networks to Reduce the Total Annual Operating Costs: An Application of the Crow Search Algorithm

This study presents a master–slave methodology to solve the problem of optimally locating and sizing photovoltaic (PV) generation units in electrical networks. This problem is represented by means of a Mixed-Integer Nonlinear Programming (MINLP) model, whose objective function is to reduce the total annual operating costs of a network for a 20-year planning period. Such costs include (i) the costs of purchasing energy at the conventional generators (the main supply node in this particular case), (ii) the investment in the PV generation units, and (iii) their corresponding operation and maintenance costs. In the proposed master–slave method, the master stage uses the Discrete–Continuous version of the Crow Search Algorithm (DCCSA) to define the set of nodes where the PV generation units will be installed (location), as well as their nominal power (sizing), and the slave stage employs the successive approximation power flow technique to find the value of the objective function of each individual provided by the master stage. The numerical results obtained in the 33- and 69-node test systems demonstrated its applicability, efficiency, and robustness when compared to other methods reported in the specialized literature, such as the vortex search algorithm, the generalized normal distribution optimizer, and the particle swarm optimization algorithm. All simulations were performed in MATLAB using our own scripts

Optimal Investments in PV Sources for Grid-Connected Distribution Networks: An Application of the Discrete–Continuous Genetic Algorithm

The problem of the optimal siting and sizing of photovoltaic (PV) sources in grid connected distribution networks is addressed in this study with a master–slave optimization approach. In the master optimization stage, a discrete–continuous version of the Chu and Beasley genetic algorithm (DCCBGA) is employed, which defines the optimal locations and sizes for the PV sources. In the slave stage, the successive approximation method is used to evaluate the fitness function value for each individual provided by the master stage. The objective function simultaneously minimizes the energy purchasing costs in the substation bus, and the investment and operating costs for PV sources for a planning period of 20 years. The numerical results of the IEEE 33-bus and 69-bus systems demonstrate that with the proposed optimization methodology, it is possible to eliminate about 27% of the annual operation costs in both systems with optimal locations for the three PV sources. After 100 consecutive evaluations of the DCCBGA, it was observed that 44% of the solutions found by the IEEE 33-bus system were better than those found by the BONMIN solver in the General Algebraic Modeling System (GAMS optimization package). In the case of the IEEE 69-bus system, the DCCBGA ensured, with 55% probability, that solutions with better objective function values than the mean solution value of the GAMS were found. Power generation curves for the slack source confirmed that the optimal siting and sizing of PV sources create the duck curve for the power required to the main grid; in addition, the voltage profile curves for both systems show that voltage regulation was always maintained between ±10% in all the time periods under analysis. All the numerical validations were carried out in the MATLAB programming environment with the GAMS optimization package

Analysis of Research Topics and Scientific Collaborations in Energy Saving Using Bibliometric Techniques and Community Detection

Concern about everything related to energy is increasingly latent in the world and therefore the use of energy saving concepts has been increasing over the past several years. The interest in the subject has allowed a conceptual evolution in the scientific community regarding the understanding of the adequate use of energy. The objective of this work is to determine the contribution made by international institutions to the specialized publications in the area of energy-saving from 1939 to 2018, using Scopus Database API Interface. The methodology followed in this research was to perform a bibliometric analysis of the whole scientific production indexed in Scopus. The world’s scientific production has been analysed in the following domains: First the trend over time, types of publications and countries, second, the main subjects and keywords, third, main institutions and their main topics, and fourth, the main journals and proceedings that publish on this topic. Then, these data are presented using community detection algorithms and graph visualization software. With these techniques, it is possible to determine the main areas of research activity as well as to identify the structures of the collaboration network in the field of renewable energy. The results of the work show that the literature in this field have substantially increased during the last 10 years

Great challenges and the application of participatory tools in the planning of the informal city. The case of Makeni, Sierra Leone.

El siguiente artículo indaga sobre la definición de modelos de planificación y herramientas de gestión para ciudades con crecimientos expansivos y amplios sectores informales, utilizando como caso de estudio la experiencia desarrollada en la ciudad de Makeni, Sierra Leona. En un proceso de varios años que continua vivo, la Escuela de Arquitectura de la Universidad San Pablo CEU (USP-CEU) ha impulsado acciones de planeamiento urbano participativo, aportando experiencia técnica desde la colaboración con la Universidad de Makeni y con el Ayuntamiento de la ciudad. Avanzando en el conocimiento paulatino de una realidad específica llena de retos, se han abordado propuestas urbanas en dos líneas fundamentales. Por un lado, mediante el desarrollo de un Plan Espacial Estratégico para Makeni, destinado a la generación de propuestas para la ciudad y su territorio; y, por otro, con la implementación del Programa de Mejoramiento de Barrios, centrado en la ciudad existente. En relación a los resultados, en el territorio de Makeni, destacan el desarrollo de las capacidades formativas de los alumnos de la universidad local, la generación de metodologías e instrumentos de planeamiento básicos, el reforzamiento de los cuadros administrativos municipales, junto a la implicación y concienciación de la población local. A nivel global, hay que destacar la definición de un marco coherente y sistemático, factible de ser replicado en otras realidades urbanas con similares características. Un aporte que resulta especialmente válido en aquellos contextos urbanos desfavorecidos que, en sus procesos de crecimiento, afrontan el mayor reto futuro vinculado a la habitabilidad a nivel global.This article investigates the definition of planning models and management tools for cities with expansive growth and broad informal sectors using the experience of the city of Makeni, Sierra Leone as a case study. In an ongoing process over several years, the School of Architecture at the University San Pablo CEU (USP-CEU) has promoted participatory urban planning actions by providing technical experience through collaboration with the University of Makeni and the Makeni City Council. In the gradual advancement of knowledge about a specific reality full of challenges, urban proposals have been approached in two fundamental ways: on the one hand, through the development of a Strategic Spatial Plan for Makeni aimed at generating proposals for the city and its territory; and on the other, with the implementation of the Neighborhood Improvement Program focused on the existing city. On a local scale in the Makeni territory, notable results include: progress in the training and abilities of local university students, the generation of methodologies and basic planning tools, the strengthening of the municipal administrative cadres, and the involvement and increased awareness of the local population. At the global level, it is important to highlight the creation of a coherent and systematic framework, which can be replicated in other urban realities with similar characteristics. This contribution is especially appropriate in those disadvantaged urban contexts that, in their growth processes, face the greatest future challenge related to habitability at the global level

Optimal Placement and Sizing of Wind Generators in AC Grids Considering Reactive Power Capability and Wind Speed Curves

This paper presents an optimization model for the optimal placement and sizing of wind turbines, considering their reactive power capacity, wind speed, and demand curves. The optimization model is nonlinear and is focused on minimizing power losses in AC distribution networks. Also, paired wind turbine and power conversion systems are treated via chargeability factor η at the peak hour. This factor represents the percentage of usage of the power conversion system in the nominal wind speed conditions, and allows to support reactive power dynamically during all periods of the day as a function of the distribution system requirements. In addition, an artificial neural network is used for short-term forecasting to deal with uncertainties in wind power generation. We assume that the number of wind power distributed generators could be from zero to three generators integrated into the system, considering unit power factors and reactive power injections to follow up the effect of reactive power compensation in the daily operation. The General Algebraic Modeling System (GAMS) is employed to solve the proposed optimization model

Application of the Multiverse Optimization Method to Solve the Optimal Power Flow Problem in Alternating Current Networks

In this paper, we solve the optimal power flow problem in alternating current networks to reduce power losses. For that purpose, we propose a master–slave methodology that combines the multiverse optimization algorithm (master stage) and the power flow method for alternating current networks based on successive approximation (slave stage). The master stage determines the level of active power to be injected by each distributed generator in the network, and the slave stage evaluates the impact of the proposed solution on each distributed generator in terms of the objective function and the constraints. For the simulations, we used the 10-, 33-, and 69-node radial test systems and the 10-node mesh test system with three levels of distributed generation penetration: 20%, 40%, and 60% of the power provided by the slack generator in a scenario without DGs. In order to validate the robustness and convergence of the proposed optimization algorithm, we compared it with four other optimization methods that have been reported in the specialized literature to solve the problem addressed here: Particle Swarm Optimization, the Continuous Genetic Algorithm, the Black Hole Optimization algorithm, and the Ant Lion Optimization algorithm. The results obtained demonstrate that the proposed master–slave methodology can find the best solution (in terms of power loss reduction, repeatability, and technical conditions) for networks of any size while offering excellent performance in terms of computation time

Parameter estimation of a thermoelectric generator by using salps search algorithm

Thermoelectric generators (TEGs) have the potential to convert waste heat into electrical energy, making them attractive for energy harvesting applications. However, accurately estimating TEG parameters from industrial systems is a complex problem due to the mathematical complex non-linearities and numerous variables involved in the TEG modeling. This paper addresses this research gap by presenting a comparative evaluation of three optimization methods, Particle Swarm Optimization (PSO), Salps Search Algorithm (SSA), and Vortex Search Algorithm (VSA), for TEG parameter estimation. The proposed integrated approach is significant as it overcomes the limitations of existing methods and provides a more accurate and rapid estimation of TEG parameters. The performance of each optimization method is evaluated in terms of root mean square error (RMSE), standard deviation, and processing time. The results indicate that all three methods perform similarly, with average RMSE errors ranging from 0.0019 W to 0.0021 W, and minimum RMSE errors ranging from 0.0017 W to 0.0018 W. However, PSO has a higher standard deviation of the RMSE errors compared to the other two methods. In addition, we present the optimized parameters achieved through the proposed optimization methods, which serve as a reference for future research and enable the comparison of various optimization strategies. The disparities observed in the optimized outcomes underscore the intricacy of the issue and underscore the importance of the integrated approach suggested for precise TEG parameter estimation

Optimal Location and Sizing of Distributed Generators in DC Networks Using a Hybrid Method Based on Parallel PBIL and PSO

This paper addresses the problem of the locating and sizing of distributed generators (DGs) in direct current (DC) grids and proposes a hybrid methodology based on a parallel version of the Population-Based Incremental Learning (PPBIL) algorithm and the Particle Swarm Optimization (PSO) method. The objective function of the method is based on the reduction of the power loss by using a master-slave structure and the consideration of the set of restrictions associated with DC grids in a distributed generation environment. In such a structure, the master stage (PPBIL) finds the location of the generators and the slave stage (PSO) finds the corresponding sizes. For the purpose of comparison, eight additional hybrid methods were formed by using two additional location methods and two additional sizing methods, and this helped in the evaluation of the effectiveness of the proposed solution. Such an evaluation is illustrated with the electrical test systems composed of 10, 21 and 69 buses and simulated on the software, MATLAB. Finally, the results of the simulation demonstrated that the PPBIL–PSO method obtains the best balance between the reduction of power loss and the processing time