Study of tropospheric scintillation effects in Ku-band frequency for satellite communication system

Scintillation is a rapid fluctuation of electromagnetic waves in terms of phase and amplitude due to a small-scale inconsistency in the transmission path (or paths) with time. Scintillation exists continuously throughout a day whether during raining or clear sky conditions. The raw signal data need to exclude other propagations factors that include signal fluctuations to further understand the scintillation studies. This paper presents the analysis of tropospheric scintillation data from January 2016 till December 2016 at Ku-band frequency of 12.202 GHz beacon signal. The experimental data from MEASAT 3B were collected and analyzed to see the effect of tropospheric scintillation. The elevation angle of the dish antenna is 77.45o. The highlighted objectives are to analyze the scintillation data at Ku-band, and to compare and validate the results with other scintillation models. The result shows that the stipulated scintillation analysis has higher amplitude, which is 0.73 dB compared to other scintillation analysis which has lower scintillation amplitude: 0.45 dB (Karasawa), 0.42 dB (ITU-R), 0.4 dB (Nadirah & Rafiqul), 0.42 dB (Van De Kamp), and 0.11 dB (Anthony & Mandeep)

A method to establish a trade-space of system requirements and life cycle cost

—Systems engineering traditionally approaches the design of systems through determination of requirements for and implementation of a system. The system is conceived as something to enable achievement of an effect with the tacit assumption that the system to be designed must achieve technical performance, including availability characteristics, which enable delivery of the whole of the intended effect. This approach determines the technical requirements of the system to ensure achievement of the system purpose under assumptions about how the system, or fleet, would be deployed to provide the intended service. Usually, cost is addressed after requirements, either to find the cheapest method to achieve the requirements or as one dimension of a trade-space analysis. In this paper, we explore a different philosophy for finding the system requirements; starting with the required system level service provision, but agnostic about the technical quality needed.We investigate a trade-space including the life cycle cost (LCC) of service provision as a contribution to determining subsystem requirements. We model the life cycle, for many variations of technical composition, using a Monte Carlo method, and show that a trade-space of LCC and requirements is likely to produce a cheaper solution than starting with sub-system requirements

A method to establish a trade-space of system requirements and life cycle cost

Systems engineering traditionally approaches design of systems through determination of requirements for and implementation of a system. The system is conceived as something to enable achievement of an effect with the tacit assumption that the system to be designed must achieve technical performance, including availability characteristics, which enable delivery of the whole of the intended effect. This approach determines the technical requirements of the system to ensure achievement of the system purpose under assumptions about how the system, or fleet, would be deployed to provide the intended service. Commonly cost is addressed after requirements, either to find the cheapest method to achieve the requirements or as one dimension of a trade-space analysis. We explore a different philosophy for finding the system requirements; starting with the required system level service provision, but agnostic about the technical quality needed. We investigate a trade-space including the life cycle cost (LCC) of service provision as a contribution to determining subsystem requirements. We model the life cycle, for many variations of technical composition, using a Monte Carlo method, and show that a trade-space of LCC and requirements is likely to produce a cheaper solution than starting with sub-system requirements

Analysis of long term tropospheric scintillation from Ku-band satellite link in tropical climate

Scintillation is the rapid signal fluctuations of amplitude and phase of a radiowave which can cause signal lossin the transmission path with time. Other propagation factors that contribute to the signal fluctuations must be omitted before using the raw data for scintillation studies. Scintillation occurs continuously whether it is under clear sky condition or raining. Therefore, during raining event, the scintillation data will be accompanied by the signal level attenuation caused by the rain. Hence, attention must be given when analyzing scintillation data during raining event. This paper presents the data analysis of the tropospheric scintillation for earth to satellite link at Ku-band. Eight months (May 2011 till December 2011) data were collected and were analyzed to see the effect of tropospheric scintillation during morning, midday, evening and midnight. In this paper, the scintillation data were analyzed during clear sky condition. Any spurious signals caused by other propagation factors were eliminated accordingly. The experimental data were collected using 2.4 m dish antenna through MEASAT 3 at 10.982 GHz. The elevation angle of the dish antenna is stationed at 77.5°. The findings show that scintillation amplitude during midday is highest if compared to morning, evening and midnight. During midnight, the scintillation amplitudes drop significantly

A framework for self-organized learning environments to develop soft skills in geographically distributed and multicultural engineering teams

This paper presents a novel framework for self-organized learning environments implemented for a virtual summer program conducted jointly by two universities involving fifteen students from various engineering majors and countries. The framework comprises eight elements: competency-centered, challenge-based learning focused on sustainable development goals, self-organizing teams, domain frameworks such as cultural awareness and disciplined agile exploratory lifecycle, self-assessment, competency evaluation, academicians as coaches and consultants, and feedback by appreciation and coaching. The framework assessment consisted of initial and exit surveys. The survey results indicated that the students demonstrated improvements in multicultural perspective, intercultural communication, and working in multicultural teams

Linking integrity with road pricing cause-and-effect model: A system dynamics simulation approach

With Malaysia's rapid urbanisation and continuous improvement of living standards, vehicle ownership and trip volume continue to grow. Increases in motor traffic in large cities and their environs result in a number of social, environmental, and economic issues, which are frequently attributable to the widespread use of automobiles as the primary mode of urban transportation. This exacerbates traffic congestion on the country's highways, particularly in urban areas such as Kuala Lumpur. This traffic congestion poses an ongoing threat to the sustainability of transport development. Thus, by using the system dynamics, this study establishes a cause-and-effect relationship regarding the implementation of road pricing as a tool for reducing congestion and a stepping stone for enhancing sustainability. Road pricing is a direct charge assessed to drivers who use the road network with the goal of reducing the number of private vehicles on the road during peak hours. The developed Causal Loop Diagram (CLD) composed of five subsystems: road congestion, road attractiveness, new road construction, public transportation, and road pricing. The road congestion, new road construction, and road pricing all encounter mutual reinforcement as a result of a variety of negative polarities. As a result, authorities should place a greater emphasis on these loopholes, as they will inevitably result in unexpected changes. Additionally, by incorporating holistic perspectives from previous works and experts in the field, CLD can aid in identifying the primary factors underlying the problem being studied. In future work, the developed CLD should be extended to the next stage of the SD model, dubbed stock-flow-diagram (SFD)

Development of a computer simulation on road pricing strategy to reduce congestion and carbon dioxide emission: A system dynamics approach

Road congestion influences the quality of lifestyle for urban areas including Kuala Lumpur, the capital city of Malaysia. It is predicted that the demand for mobility in the city will be increased tremendously in the next ten years. Consequently, this problem has contributed to air pollution caused by carbon dioxide emissions. One of the solutions suggested by the expertise is road pricing via a direct charge to drivers who use the road during peak hours. In this regard, this research aims to develop a computer simulation based on a system dynamic approach for mitigating congestion and carbon dioxide emission via a road pricing strategy. Firstly, the identified variables were correlated to understand the behavior of the system. Subsequently, the correlated variables were embedded in the stock-flow diagram based on the system dynamics approach to investigate how a variable affects another variable. Then, the developed model was simulated for evaluating the impact of road pricing strategy in reducing congestion and carbon dioxide emission. As a result, the emission of carbon dioxide can be reduced to 6 percent in six days if road pricing is implemented. From the managerial perspective, this research helps highway stakeholders in Malaysia towards making a better decision in enforcing road pricing strategy in the fast-moving city for a better lifestyle and environment

Reliability model and proposed maintainability activities of earth station system

Earth station system plays a big role in communications industry. To ensure that the earth station system functioning throughout specified period of time, the reliability and maintainability of the system needs to be analyzed. This paper presents the analysis on the reliability of 2-parallel and 3-parallel configurations of earth station system with Mean Time Between Failure of 6 months, 2.5 years, 3.7 years, 4.5 years and 5 years using secondary data obtained from Monte Carlo generator in Matlab. A new reliability model is created based on the results obtained. Suitable maintenance activities are also proposed for the earth station system

Analysis of reliability prediction and maintainability activities of an earth station system using parallel configurations

The recent news regarding the Malaysian satellite, MEASAT-3; which suffered an anomaly has caused the satellite to drift out of its geostationary orbit, and the uncontrolled re-entry of the Chinese Long March 5B rocket in 2021 had sparked high alarms in satellite operators industry. Due to the satellite communication system failure, the government had loss a massive amount of money. Hence, it is essential to equip the system with a sustainable framework design which can be achieved through an optimum system reliability and maintainability. Subsystem redundancies, multiple testing during the planning stage, and selection of only the best components for its subsystems can improve the system reliability. Also, relevant maintenance activities should be performed frequently to avoid cost overruns and unforeseen failures. This paper presents an analysis of the reliability and maintainability of an Earth Station system using Monte Carlo simulations. The results show that the highest reliability value is obtained for the 3-parallel configuration. Suitable maintenance activities are also suggested to assist with the maintainability of the Earth Station system

Sustainable framework for a geostationary satellite control earth station system using parallel configuration

Earth station system plays an important role to ensure that a satellite communication system runs efficiently. Redundancies of the subsystems and regular maintenance planning can improve the earth station system. Organising system affordability can be challenging as more redundancies would acquire more maintenance. Thus, a sustainable framework that considers an earth station system's reliability, cost, and maintainability was modelled. 2-parallel, 3-parallel, and 4-parallel earth station system configurations were studied with five mean time between failures (MTBF). The results showed that an earth station that was configured with 2-parallel configuration provided an optimum reliability system performance though both 3-parallel and 4-parallel configuration provided higher reliability. Moreover, the 2-parallel configuration was also cheaper in terms of operational cost if compared to the 3-parallel and the 4-parallel configurations. Hence, this sustainable framework comprising the reliability and operational cost elements were modelled based on the 2-parallel configuration with the proposed maintenance activities. Moreover, the computed root mean square (RMS) values for both new reliability and new operational cost models yielded smallest values of 20.84% and 22.82% respectively. Thus, these RMS values for both reliability and operational cost models based on 2-parallel configuration are suitable to be applied in the earth station system design