Report on the 1993 IFAC World Congress standards and guidelines session

This brief note reviews five papers which were presented at the 1993 IFAC World Congress, on the theme 'standards and guidelines for computer-aided control engineering (CACE)'. This session was organized as part of the CACE Software Standardization Initiative, a combined effort of the IFAC and IEEE Control System Society committees on standards. The motivation of this report is to note the substantial progress that was made in this initiative, and to provide the basis for further discussion and work. The papers under review were concerned with integrated design environments, the use of the EXPRESS language for defining standard data structures, database management, user interfaces, and the modeling and simulation of hybrid systems.

Governança no setor público: diagnóstico das práticas de gestão da Polícia Federal à luz do estudo 13 do PSC/IFAC

No Brasil, a sociedade observa atônita a corrupção, o descaso com o dinheiro público e a prestação de serviços essenciais, que ficam aquém de suas expectativas. Para que haja mudanças no setor público, torna-se imprescindível a adoção de boas práticas de governança que promovam a adequação dos serviços prestados, de forma que possam se tornar mais eficientes e eficazes. Nessa seara, incluem-se as instituições provedoras de segurança pública, que, para cumprir suas atribuições, precisam estar bem equipadas, possuir recursos humanos suficientes e apresentar uma gestão íntegra, transparente e responsável. Nesse contexto, esta dissertação teve como objetivo diagnosticar as práticas de gestão da Polícia Federal e compará-las aos padrões de boa governança no setor público recomendados pelo Estudo 13 do PSC/IFAC. Os resultados demonstraram que grande parte das práticas de gestão adotadas pela Polícia Federal apresenta-se em conformidade com as boas práticas de governança sugeridas no referido Estudo. Destacaram-se positivamente as práticas relacionadas a padrões de comportamento e a estruturas e processos organizacionais. Por outro lado, constatou-se a inexistência de um código de conduta próprio e a ausência de treinamento inicial do membro do grupo governante, quando de sua nomeação ou durante seu mandato. Quanto às práticas de gestão relacionadas a controle, foram diagnosticadas falhas em gestão de riscos, em decorrência da falta de aplicação em todos os objetivos organizacionais. Comportamento semelhante foi observado no controle interno, que, apesar de ser constantemente monitorado, não pode ser avaliado quanto à adequação e efetividade. Quanto às práticas relativas a relatórios externos, constatou-se que a instituição elabora relatórios equilibrados, transparentes e de fácil compreensão, em conformidade com a legislação vigente e padrões contábeis. Entretanto, a Polícia Federal não demonstrou expressamente o cumprimento de códigos de governança, tampouco empregou indicadores de desempenho suficientes para mostrar que os recursos vêm sendo usados com eficiência. Concluiu-se que a Polícia Federal adota boas práticas de gestão, mas ainda pode implementar outras recomendações de boa governança, contribuindo para que o país caminhe para atingir a excelência na gestão dos recursos públicos e assuma uma posição de destaque no cenário internacional.

Análisis de la aplicación de las Normas Internacionales de Educación para Contadores Públicos, emitidas por IFAC, realizado en la ciudad de San Miguel

La presente investigación, contiene un análisis sobre el grado de aplicación de las Normas Internacionales de Educación para Contadores Profesionales emitidas por la Federación Internacional de Contadores por sus siglas en ingles IFAC, para lo cual se realizó con una muestra de Contadores y Auditores en el Ejercicio Profesional de la ciudad de San Miguel, procurando proporcionar resultados apegados a la realidad. Se pretende obtener información para hacer un análisis sobre las Normas Internacionales de Educación para Contadores Profesionales y determinar su grado de aplicación en los Contadores y Auditores en el ejercicio profesional en la Ciudad y de San Miguel, estudiamos las Normas Internacionales de Educación para Contadores Profesionales emitidas por la Federación Internacional de Contadores (IFAC), y conocer la opinión de los Estudiantes Egresados de Contaduría Pública y / o Contadores y Auditores en el ejercicio profesional sobre las Norma de Educación Continuada emitida por el Consejo de Vigilancia de la Profesión de la Contaduría Pública y Auditoría. La investigación se desarrolló para determinar el grado de aplicación de la Norma de Educación Continuada y la Norma Internacional de Educación para Contadores Profesionales en el área de San Miguel. De los contadores se seleccionaron 21 profesionales de manera aleatoria que ejercen contabilidad y/o auditoría de los cuales 17 laboran en su totalidad en el área metropolitana y los restantes se desarrollan además en otras zonas del país. La principales áreas en las que desarrollan los 21 contadores encuestados son: el 47.7% labora en una firma de auditoría y un 28.6% en contabilidad, de los cuales corresponden a diez y seis contadores respectivamente de la muestra tomada. Asimismo cinco de ellos se desempeñan en el sector privado equivalente al 23.8%. Finalmente dos contadores encuestados laboran en el sector público y dos en el sector financiero en un equivalente al 4.8% en cada área.

Lineamientos para la aplicación de la Norma internacional sobre control de calidad No.1, emitida por la Federación internacional de contadores (IFAC), para firmas de auditoría.

Ante la problemática observada sobre la limitada información existente para la implementación de la Norma Internacional de Control de Calidad No 1 en las firmas de auditoría de El Salvador, y como respuesta para determinar cuáles son las principales causas que la originan, se decidió efectuar esta investigación que tiene como finalidad determinar si la aplicación de lineamientos basados en la norma, permiten a las firmas proporcionar calidad en los trabajos que desarrollan. Por tal razón, el objetivo final de este trabajo es proponer una guía para la implantación de la norma, que contribuya al control y supervisión de las firmas. La investigación se basó en el método hipotético deductivo, empleando un estudio de tipo interpretativo descriptivo, que mediante técnicas e instrumentos como el muestreo, la encuesta y la sistematización bibliográfica permitió determinar las valoraciones y conclusiones siguientes: Las firmas de auditoría están compuestas por un mayor número de asistentes, los cuales conocen en alguna medida el contenido y aplicación de la Norma Internacional de Control de Calidad No 1; sin embargo, aun con un conocimiento aceptable, las firmas no poseen políticas y procedimientos de calidad de manera integral para sus prácticas de auditoria. Así mismo, se conoció que la mayoría de sus dirigentes promueven en el personal que los trabajos sean desarrollados con estándares de calidad. Para esto se apoyan de memorándums y circulares, pues se consideran más accesibles para comunicar y documentar las decisiones tomadas al interior. En el mismo sentido, se logró observar que la mayoría de las firmas ejecutan evaluaciones de calidad continuas, a través de la supervisión de su personal; sin embargo, hay otros factores que son pasados por alto al no tener bien establecidos y por escrito los lineamientos de la empresa. Que se suma con los medios poco efectivos para divulgar la información. Por lo tanto, se sugiere dar seguimiento y fortalecer programas de capacitación relacionados con la instrucción en los principios éticos y el desarrollo del trabajo fijados por el Consejo de Vigilancia de la Profesión de la Contaduría Pública y Auditoria. Complementar el aspecto de la supervisión, con los demás elementos que integran un sistema de control de calidad; así como fortalecer la cultura interna de estos estándares; esto, mediante parámetros de medición que verifiquen los resultados obtenidos por la implementación y promoción de políticas y procedimientos. Por último, tomar como herramienta para documentar y comunicar decisiones basadas en la norma, en esta propuesta.

Teaching crabs to walk straight : is there a place for ethics education in Malaysian accountancy courses?

Recent releases from the International Federation of Accountants (IFAC) highlight the importance of ethics education. Academic institutions employ varying methods of teaching ethics and place varying levels of emphasis on ethics teaching during a business/accounting degree. This paper attempts to evaluate whether teaching ethics to final year accountancy students is beneficial. At the commencement of a semester 85 final year accounting students were given five ethical scenarios on which to make an ethical decision. During the semester they were subject to two different methods of teaching ethics, a traditional lecture/tutorial process and a group assignment. ----- After a significant gap, students were re-presented with the ethical scenarios and asked what action they now considered appropriate. In all five instances students offered a more ethical response the second time. When asked to evaluate the methodologies the students considered both training methods to have a positive effect on their ethical thinking. The results suggest it is beneficial to include ethics teaching in accountancy courses, if the profession’s goal of ethical practitioners is to be achieved.

Design and evaluation of a prototype tracking system

In this paper, we present the design and construction of a prototype target tracking system. The experimental set up consists of three main modules for moving the object, detecting the motion of the object and its tracking. The mechanism for moving the object includes an object and two stepper motors and their driving and control circuitry. The detection of the object’s motion is realized by photo switch array. The tracking mechanism consists of a laser beam and two DC servomotors and their associated circuitry. The control algorithm is a standard fuzzy logic controller. The system is designed to operate in two modes in such a way that the role of target and tracker can be interchanged. Experimental results indicate that the fuzzy controller is capable of controlling the system in both modes.

A first extension of geometric control theory to underwater vehicles

This paper serves as a first study on the implementation of control strategies developed using a kinematic reduction onto test bed autonomous underwater vehicles (AUVs). The equations of motion are presented in the framework of differential geometry, including external dissipative forces, as a forced affine connection control system. We show that the hydrodynamic drag forces can be included in the affine connection, resulting in an affine connection control system. The definitions of kinematic reduction and decoupling vector field are thus extended from the ideal fluid scenario. Control strategies are computed using this new extension and are reformulated for implementation onto a test-bed AUV. We compare these geometrically computed controls to time and energy optimal controls for the same trajectory which are computed using a previously developed algorithm. Through this comparison we are able to validate our theoretical results based on the experiments conducted using the time and energy efficient strategies.

Computationally efficient methods for solving time-variable-order time-space fractional reaction-diffusion equation

Fractional differential equations are becoming more widely accepted as a powerful tool in modelling anomalous diffusion, which is exhibited by various materials and processes. Recently, researchers have suggested that rather than using constant order fractional operators, some processes are more accurately modelled using fractional orders that vary with time and/or space. In this paper we develop computationally efficient techniques for solving time-variable-order time-space fractional reaction-diffusion equations (tsfrde) using the finite difference scheme. We adopt the Coimbra variable order time fractional operator and variable order fractional Laplacian operator in space where both orders are functions of time. Because the fractional operator is nonlocal, it is challenging to efficiently deal with its long range dependence when using classical numerical techniques to solve such equations. The novelty of our method is that the numerical solution of the time-variable-order tsfrde is written in terms of a matrix function vector product at each time step. This product is approximated efficiently by the Lanczos method, which is a powerful iterative technique for approximating the action of a matrix function by projecting onto a Krylov subspace. Furthermore an adaptive preconditioner is constructed that dramatically reduces the size of the required Krylov subspaces and hence the overall computational cost. Numerical examples, including the variable-order fractional Fisher equation, are presented to demonstrate the accuracy and efficiency of the approach.

Optimal power system stabilizer tuning in multi-machine system via an improved differential evolution

Power system stabilizer (PSS) is one of the most important controllers in modern power systems for damping low frequency oscillations. Many efforts have been dedicated to design the tuning methodologies and allocation techniques to obtain optimal damping behaviors of the system. Traditionally, it is tuned mostly for local damping performance, however, in order to obtain a globally optimal performance, the tuning of PSS needs to be done considering more variables. Furthermore, with the enhancement of system interconnection and the increase of system complexity, new tools are required to achieve global tuning and coordination of PSS to achieve optimal solution in a global meaning. Differential evolution (DE) is a recognized as a simple and powerful global optimum technique, which can gain fast convergence speed as well as high computational efficiency. However, as many other evolutionary algorithms (EA), the premature of population restricts optimization capacity of DE. In this paper, a modified DE is proposed and applied for optimal PSS tuning of 39-Bus New-England system. New operators are introduced to reduce the probability of getting premature. To investigate the impact of system conditions on PSS tuning, multiple operating points will be studied. Simulation result is compared with standard DE and particle swarm optimization (PSO).

A Flight control scheme to improve position tracking performance of rotary-wing UASs

This paper outlines an innovative and feasible flight control scheme for a rotary-wing unmanned aerial system (RUAS) with guaranteed safety and reliable flight quality in a gusty environment. The proposed control methodology aims to increase gust-attenuation capability of a RUAS to ensure improved flight performance when strong gusts occur. Based on the design of an effective estimator, an altitude controller is firstly constructed to synchronously compensate for fluctuations of the main rotor thrust which might lead to crashes in a gusty environment. Afterwards, a nonlinear state feedback controller is proposed to stabilize horizontal positions of the RUAS with gust-attenuation property. Performance of the proposed control framework is evaluated using parameters of a Vario XLC helicopter and high-fidelity simulations show that the proposed controllers can effectively reduce side-effect of gusts and demonstrate performance improvement when compared with the proportional-integral-derivative (PID) controllers.

A neural-network based flight controller for UASs

This paper presents a nonlinear gust-attenuation controller based on constrained neural-network (NN) theory. The controller aims to achieve sufficient stability and handling quality for a fixed-wing unmanned aerial system (UAS) in a gusty environment when control inputs are subjected to constraints. Constraints in inputs emulate situations where aircraft actuators fail requiring the aircraft to be operated with fail-safe capability. The proposed controller enables gust-attenuation property and stabilizes the aircraft dynamics in a gusty environment. The proposed flight controller is obtained by solving the Hamilton-Jacobi-Isaacs (HJI) equations based on an policy iteration (PI) approach. Performance of the controller is evaluated using a high-fidelity six degree-of-freedom Shadow UAS model. Simulations show that our controller demonstrates great performance improvement in a gusty environment, especially in angle-of-attack (AOA), pitch and pitch rate. Comparative studies are conducted with the proportional-integral-derivative (PID) controllers, justifying the efficiency of our controller and verifying its suitability for integration into the design of flight control systems for forced landing of UASs.