Design study for LANDSAT D attitude control system

A design and performance evaluation is presented for the LANDSAT D attitude control system (ACS). Control and configuration of the gimballed Ku-band antenna system for communication with the tracking and data relay satellite (TDRS). Control of the solar array drive considered part of the ACS is also addressed

Design study for LANDSAT-D attitude control system

The gimballed Ku-band antenna system for communication with TDRS was studied. By means of an error analysis it was demonstrated that the antenna cannot be open loop pointed to TDRS by an onboard programmer, but that an autotrack system was required. After some tradeoffs, a two-axis, azimuth-elevation type gimbal configuration was recommended for the antenna. It is shown that gimbal lock only occurs when LANDSAT-D is over water where a temporary loss of the communication link to TDRS is of no consequence. A preliminary gimbal control system design is also presented. A digital computer program was written that computes antenna gimbal angle profiles, assesses percent antenna beam interference with the solar array, and determines whether the spacecraft is over land or water, a lighted earth or a dark earth, and whether the spacecraft is in eclipse

Severe storms observing satellite study

Payload distribution and the attitude control system for the multi-mission modular spacecraft/StormSat configuration are discussed. The design of the advanced atmospheric sounder and imaging radiometer (AASIR) gimbal drive and its servomechanism is described. Onboard data handling, data downlink communications, and ground data handling systems are developed. Additional topics covered include: magnetic unloading at synchronous altitude, north-south stationkeeping, and the feasibility and impact of flying the microwave atmospheric sounding radiometer (MASR) as an additional payload

Comparação de modelos de agentes para gerenciamento de redes :: uma abordagem via simulação /

Dissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico

An Interpretable Machine Learning Approach for Identifying Occupational Stress in Healthcare Professionals

In the last few years, several scientific studies have shown that occupational stress has a significant impact on workers, particularly those in the healthcare sector. This stress is caused by an imbalance between work conditions, the worker’s ability to perform their tasks, and the social support they receive from colleagues and management professionals. Researchers have explored occupational stress as part of a broader study on affective systems in healthcare, investigating the use of biomarkers and machine learning approaches to identify early conditions and avoid Burnout Syndrome. In this paper, a set of machine learning (ML) algorithms was evaluated using statistical data on biomarkers from the Affective Road database to determine whether the use of explanations can help identify stress more objectively. This research integrates explainability and machine learning to aid in the identification of various levels of stress, which has not been previously evaluated for the domain of occupational stress. The Random Forest is the best-performing model for this assignment, followed by k-Nearest Neighbors and Neural Network. Later, explainers were applied to the Random Forest, highlighting feature importance, partial dependencies between characteristics, and a summary of the impact of features on outputs based on their values

Precision Pointing Control System (PPCS) system design and analysis

The precision pointing control system (PPCS) is an integrated system for precision attitude determination and orientation of gimbaled experiment platforms. The PPCS concept configures the system to perform orientation of up to six independent gimbaled experiment platforms to design goal accuracy of 0.001 degrees, and to operate in conjunction with a three-axis stabilized earth-oriented spacecraft in orbits ranging from low altitude (200-2500 n.m., sun synchronous) to 24 hour geosynchronous, with a design goal life of 3 to 5 years. The system comprises two complementary functions: (1) attitude determination where the attitude of a defined set of body-fixed reference axes is determined relative to a known set of reference axes fixed in inertial space; and (2) pointing control where gimbal orientation is controlled, open-loop (without use of payload error/feedback) with respect to a defined set of body-fixed reference axes to produce pointing to a desired target

A body sensor network simulation platform for medical applications

Body Sensor Networks (BSN) is an important technology in providing ubiquitous healthcare services. These sensors are capable of supplying medical professionals with data collected from a patient outside the hospital environment. Remotely acquired information has enormous application potential and can assist medical professionals to provide fast and accurate assistance to injured people at accidents sites, minimizing the risk of further complications by reducing delays in the diagnosis process. Despite the great benefits of such applications, there is a gap in the state-of-art techniques that allow the creation and testing of such high-level and critical applications. This paper presents a body sensor network simulation environment as a response to that need, providing a tool that plays a key role in assisting the development of critical healthcare applications through an emulated healthcare-specific hardware, which can be used to test applications in a controlled environment, considering the demands of the medical field

Núcleo multithreaded para agentes de gerenciamento osi: implementação e avaliação de desempenho

Nos últimos anos, os requisitos de gerenciamento para redes de computadores, tem exigido que plataformas de gerenciamento sejam construídas levando-se em conta os atuais avanços tecnológicos, em função da grande variedade e capacidade dos elementos disponíveis nestes ambientes. Este trabalho apresenta a introdução de tecnologias de computação de alta performance no desenvolmento de aplicações de gerenciamento de redes. Neste artigo, é apresentada uma proposta de um núcleo multithreaded para agentes de gerenciamento OSI/ISO [1], juntamente com sua modelagem, simulação e avaliação de desempenho. Para efeitos de comparação com outros modelos de agentes, uma versão unthreaded será utilizada, a qual segue o mesmo modelo dos núcleos atualmente implementados por plataformas de gerenciamento comerciais e/ou de projetos acadêmicos.Eje: Procesamiento distribuido y paralelo. Tratamiento de señalesRed de Universidades con Carreras en Informática (RedUNCI

Núcleo multithreaded para agentes de gerenciamento osi: implementação e avaliação de desempenho

Nos últimos anos, os requisitos de gerenciamento para redes de computadores, tem exigido que plataformas de gerenciamento sejam construídas levando-se em conta os atuais avanços tecnológicos, em função da grande variedade e capacidade dos elementos disponíveis nestes ambientes. Este trabalho apresenta a introdução de tecnologias de computação de alta performance no desenvolmento de aplicações de gerenciamento de redes. Neste artigo, é apresentada uma proposta de um núcleo multithreaded para agentes de gerenciamento OSI/ISO [1], juntamente com sua modelagem, simulação e avaliação de desempenho. Para efeitos de comparação com outros modelos de agentes, uma versão unthreaded será utilizada, a qual segue o mesmo modelo dos núcleos atualmente implementados por plataformas de gerenciamento comerciais e/ou de projetos acadêmicos.Eje: Procesamiento distribuido y paralelo. Tratamiento de señalesRed de Universidades con Carreras en Informática (RedUNCI

OLSR Fuzzy Cost (OLSR-FC): an extension to OLSR protocol based on fuzzy logic and applied to avoid selfish nodes

The mobile ad-hoc networks (MANET) are those whose nodes have mobility, energy restriction and operate simultaneously as end systems and router. One of the main problems found in MANETs is the occurrence of selfish nodes, which are those that refuse to route packets for other nodes. To address the issue of selfish nodes in MANETs and improve the flow of traffic in these networks, this paper proposes an extension to the OLSR protocol, based on Fuzzy logic, called OLSR Fuzzy Cost (OLSR -FC). Using the NS-2 simulator, the OLSR-FC proposal was compared to other extensions of OLSR protocol (e.g., OLSR-ETX, OLSR-ML e OLSR-MD) concerning the performance metrics: packet loss, end-to-end delay, Jitter, power consumption, routing overhead and throughput. The results showed that OLSR-FC obtains better performance than the evaluated extensions, avoiding selfish nodes and selecting routes whose links have little packet losses