- CHAPTER 2
For a gasoline-powered passenger automobile, consider the following subsystems: Drive Train, Frame and Body, and Electrical System. For each of these, group together their major components using the principles of significance (performs an important function), singularity (largely falls within a simple discipline), and commonality (found in a variety of system types).
An automobile contains different mechanical systems, for example, drive train, electrical system, frame and body, braking system, and combustion system. It plays a critical role in people’s lives by helping them with transportation from one place to another. According to the principle of significance each of the functional elements of the system must perform a distinct and significant function that involves different simple functions. In commonality, the function executed by the element is replicated in a wide range of systems. Singularity, on the other hand, entails each of the functions belonging within the technical scope of an engineering specialist discipline (Kossiakoff, & Sweet, 2003).
The main components of the drive train can be grouped together in; the gear box, clutch, transmission, differential, rear axle, and propeller shaft. Further, the main components of the frame and body of the gasoline-powered passenger automobile include spoiler, rocker, grill, pillar, bonnet, radiator, bumper, doors, sun-roof, and rims, in one grouping. A group of the major components of the automobile’s electrical system includes the alternator, speedometer, distributor, ignition box, ammeter, electronic timing controller, and battery.
The three criteria of significance, singularity, and commonality help make the elements representative and self-consistent. As such, each element is neither inordinately complex nor trivially simple and have wide applications (Kossiakoff, & Sweet, 2003). A drive train works in a way that the engine produces power to drive the flywheel, which works with the transmission to regulate the power quantities entering the different components of the drive train. The drive train then rotates to produce power to a differential, which puts the wheel in motion.
The electrical system is a closed circuit and has a battery as its independent power source. The system operates on a small fraction of the power, and other than the major charging (i.e., ignition and starting circuits) it has other circuits to power lights, electrical instrument gauges and sensors, the radio, magnetically operated locks, and heating elements. A switch or relays are used to open and close the circuits (Kossiakoff, & Sweet, 2003).
- CHAPTER 3
The space shuttle is an example of an extremely complicated system using leading edge technology. Give three examples of shuttle components that you think represented unproven technology at the time of its development, and which much have required extensive prototyping and testing to reduce operational risks to an acceptable level.
The space shuttle has three major components which represented unproven technology during its development stages. These components include the orbiter, external tank, and rocket boosters. The components have gone through extensive prototyping and testing as engineers were perfecting the shuttle to mitigate operational risks to acceptable levels. The orbiter houses the crew while the external tank stores the fuel for the space shuttle’s main engines (Kossiakoff, & Sweet, 2003). The solid rocket boosters propel the shuttle’s lift during the initial two minutes of the flight or take off. Apart from the external fuel tank, which burns up once the shuttle has launched to the atmosphere, the other parts are reusable. The orbiter is 121 feet, a 57-foot tail height and 78-foot wingspan. It is made mostly of aluminum at the size of a commercial airliner. It has a 15 feet diameter and 60 feet long payload.
The orbiter’s landing weight depends on the mission of the space shuttle. The orbiter can last about 100 space missions. It has a mid-fuselage and forward fuselage which include the payload bay, the wing, main landing gear, and cockpit, crew cabin, and work areas, respectively (Kossiakoff, & Sweet, 2003). The orbiter is a glider that can be accurately and safely piloted to a runway landing after the shuttle has completed its space mission. Initially, capsules provided limited accuracy after reentry, although the shuttle’s design allowed for a safe return or easy separation for transportation purposes. Research and trial and error led to the growth of the shuttle as it is today. Body designs were lifted, from wedge-shaped designs, for example, the Martin Marietta X-24A, which utilized their whole structure to generate lift.
The orbiter, therefore, is a lifting body with attached wings for added lift to provide the shuttle with the gliding ability for landing at runways. The Department of Defense required the cross-range capability to facilitate landings at remote bases. Over time, a vertical stabilizer or tail were included for more stability. The tail includes a rudder to control the horizontal orientation of the shuttle and can split apart to act as a speed brake. The main engines, orbital maneuvering system, wing aft spar, and the reaction control system pods are housed in the aft fuselage (Kossiakoff, & Sweet, 2003).
The external tank is 28.6 feet in diameter and 154 feet long and is made of aluminum alloys. Its weight when empty is 78,000 pounds. They contain liquid hydrogen and liquid oxygen. As such, the external tank is the space shuttle system’s major part that is not reused after each mission. Solid rocket boosters, the other component that represented unproven technology during development, are the largest solid propellant motors and were fist utilized on a manned spacecraft. Their motors are made of 11 weld-free steel sections joined together with high-strength steel pins. The motor measures 116 feet long and 6 feet in radius, with a million pounds of solid propellant which combusts at 5,800 degrees Fahrenheit, as well as, liftoff thrust of 2.65 million pounds (Kossiakoff, & Sweet, 2003).
The component’s exhaust nozzles have a gimble to help with pitch, yaw, and roll control for steering the orbiter as it ascends. The solid propellant is made of a catalyst (iron oxide powder), oxidizer in the form of ammonium perchlorate and atomized aluminum powder, which acts at the fuel. It also has a curing agent and a binder. Its booster combusts at the same time as the main engines, though for two minutes to provide the needed thrust for orbital altitude. Booster casings detach themselves from the external tank after covering 24 miles (Kossiakoff, & Sweet, 2003).
- CHAPTER 3
State the functions that a household automatic dishwasher performs during its operation cycle. For each function, indicate the primary medium (signals, data, material, or energy) involved. Describe the physical elements involved in the implementation of each of the above functions.
A household automatic dishwasher is used for cleaning utensils. It removes dirt particles from utensils using chemical and mechanical reactions where detergent or soap and hot water is sprayed to the utensils (Kossiakoff, & Sweet, 2003). The dishwasher then scrubs off the loaded utensils to remove the dirt particles (material). After that, the utensils are dried through exposure to hot air. For the performance and functioning of the dishwasher, cold water is added into the machine and heated at about 86 degrees to 113 degrees Fahrenheit (data). Energy enables the detergent or soap water dispenser opens and the utensils are sprayed with the mixture in jets for a specific period.
Once the set time is finished (signal), the dispenser then closes off and it drains the dirt. After that, hot air is allowed in to enable the dishes to dry (Kossiakoff, & Sweet, 2003). The dishwasher contains a pump that sprays water to the dishwasher’s sidewalls and later directs the dirty water the its drain. It helps regulate the time each cycle takes. Further, the dishwasher has a temperature sensor that monitors the temperature at which to clean the dirt off the utensils and water medium (energy). It further contains a water level sensor to help regulate the water level and prevent any water from overflowing. An electrical heating element is used to heat the water to the required temperature to remove all the dirt.
The elements involved in the implementation of dishwasher’s functions include the spray towers or arms, which differ in placement, shape, and size. The spray arms spray water on the dishes in the top and bottom racks. Other elements include the filtration system, racks, door latch, silverware basket, heating element, detergent dispenser, circulation motor or pump, water inlet valve, and control pad. The heating element raises the water and air temperature during the washing cycle and drying cycle, respectively. The control pad helps select the wash cycle and options, in addition to displaying any error messages using signals. Racks hold items securely during the washing and drying cycle. The door latch secures the machine’s door closed while the inlet valve controls the amount of water used during each cycle. Circulation motor pumps water into the dishwasher tub while the filtration system filters out dirty water and protects the pump from clogging (Kossiakoff, & Sweet, 2003).
- CHAPTER 4
There are number of risk mitigation methods for dealing with program risks. Discuss, in general, how you would use risk mitigation methods to reduce risk criticality from High to Medium.
Risk mitigation involves developing actions and options to boost opportunities and mitigate threats to project objectives. There are various risk mitigation techniques for dealing with program risks to reduce them from high to medium. These methods include special analysis and tests, rapid prototyping, management reviews, fallback alternatives, relief of excessive requirements, and special engineering oversight. An application of these risk mitigation methods would reduce the criticality of the risk. Reduction of the severity and impact of the risk leads to a reduction of the loss incurring.
However, the criticality and type of the risk depend on the methods to be implemented in the process (Kossiakoff, & Sweet, 2003). For instance, a high criticality of risk necessitates short-term measures and effective methods since high criticality risks lead to more losses. The risk mitigation method of management reviews could also be applied in high criticality risks. As such, a review of the systems engineering and their design could reduce the risk through modification and redesigning. Additionally, by identification of risks and application of the suitable risk mitigation method mitigate losses to an organization.
To reduce risk criticality from High to Medium, it is important to control the risk by implementing actions to mitigate its likelihood or impact. It would be also crucial to watch or monitor the risk environment for any changes that impact the nature of the risk. One would have to intensify management and technical reviews of the engineering process (Kossiakoff, & Sweet, 2003). A special analysis and testing of critical design items would be done followed by a rapid prototyping and test feedback. The risk manager would institute a special oversight of selected component engineering. An initiation of fallback parallel developments and relieving critical design requirements would help reduce risk criticality.
Controlling of risks involves performing analyses of different reduction methods. Seeking out potential solutions from similar risk situations. However, it is important to take special care when assessing architectural changes as well as their consequences. In watching or monitoring of the risk situation, one should resists operating on cruise control once a risk has been identified and plan hatched to manage it. Reduction of risk from high to medium would entail revisiting the basic risk assumptions and premises. The systems engineer should scan the environment to ascertain any changes in the situation and whether there are any impacts on the nature or impact of the risk (Kossiakoff, & Sweet, 2003).
- CHAPTER 5
What is meant by “measures of effectiveness”? For the effectiveness analysis of a sport utility vehicle (SUV), list what you think would be the eight most important characteristics that should be exercised and measured in the analysis.
Measures of Effectiveness (MOE) refers to the measures meant to relate to the achievement of results’ accomplishments, mission, and goals. MOE evaluate the outcomes expected from a framework and are communicated as probabilities that such framework would be executed as expected. It is a measurement of effective a problem can be solved. A sport utility vehicle (SUV) is vehicle that combines the features of an off-road vehicle and a road-going passenger car. It is built like a station wagon, but with a light-truck chassis (Kossiakoff, & Sweet, 2003). However, any car with a raised ground leeway and an accessible all-wheel drive can be referred to as a SUV.
The goal or purpose of a SUV determines the effectiveness analysis. People acquire SUVs for different purposes, for example, for a family trip, which would then ensure different characteristics for measuring an analysis (Kossiakoff, & Sweet, 2003). For a family trip SUV, the characteristics to be exercised and measured include size, use, weight, design, fuel consumption, durability, space, and cost. One must consider the size of the SUV depending on the number of items to take while on a trip in addition to the number of people to board the vehicle. One would ask themselves whether the car would accommodate more than five people. SUVs come in different sizes, for example, medium, mini, full, and extended lengths.
The use of the SUV, for example, for rough road trips or smooth surfaces. The use of the car will follow its ability to provide comfort during the journey. One would also look for the design of the SUV, which could be assessed in terms of center of gravity, body, and aerodynamics. It would be crucial to ascertain the cost of the car, in terms of whether it fits one’s budget. Its durability would involve how long the SUV would serve the user while space entails the car’s ability to accommodate at least six people comfortably. An important characteristic to consider is the vehicle’s fuel consumption, which go together with the weight of the car. Therefore, one would have to ask themselves whether the car is fuel efficient. Regarding weight, the SUV needs to be efficient when in motion. Weight, however, compromises both time and speed while the vehicle is moving (Kossiakoff, & Sweet, 2003).
- CHAPTER 6
What role does exploratory research and development conducted prior to the establishment of a formal system acquisition program play in advancing the objective of a system acquisition program? What are the main differences between the organization and funding of R&D programs and system development programs. (This question requires you to stretch you insights, since the textbook does not give a template answer. To answer this question effectively, reflect on the following questions: What are key characteristics of R&D that have management impacts? What do we mean by exploratory R&D, and where does it fit in the overall system development process? How does managing an R&D effort differ from managing a traditional engineering system development project, e.g., designing and building a new house?)
Exploratory research is an investigation of an unclearly defined problem to enable the researcher understand the existing problem without providing conclusive results. Exploratory research and development (R&D) come with risks due to the unfamiliar nature of the technologies researched. It generates a more inclusive set of user attributes that introduce transparency in decision making. The characteristics of R&D include uncertainty of research outcome and difficulties in measuring results when research tasks are unique. Further, it involves difference in attitudes, values, and expectations from the people element. R&D is associated with uncertainty of results, budget, and duration as it is the stage from scientific research to experimental development (Kossiakoff, & Sweet, 2003).
Exploratory research delves into the unfamiliar nature of technologies where no consensus exists. Researchers look for methodologies that add value to the process and increase the success rate of the exploratory research process, which makes it fit in the overall system development process. Exploratory R&D helps maximize innovation, increase accountability, and schedule slippage through performance measurement, alignment of strategies, and preplanning in exploratory design projects. It is, thus, a crucial knowledge building which seeks to improve relevant performance parameters of new technologies to apply the knowledge in useful use. The benefits of exploratory R&D include improving performance, advancing the maturity of a technology, and reduce risks.
System development programs include the process that define, design, test, and implement a new software program or application. It includes the internal development of customized systems, acquisition of third party developed software, and building of database systems. Written procedures and standards guide the processing functions of the information systems. Research funding, on the other hand, covers any funding for scientific research and is obtained through a competitive process where potential projects are evaluated and the most promising receives the financing (Kossiakoff, & Sweet, 2003). With system development, the management defines and implements standards suitable for the system development life cycle methodology for implementing the system.
- CHAPTER 7
Both the concept exploration and concept definition phases analyze several alternative system concepts. Explain the principal differences in the objectives of this process in the two phases and in the manner in which the analysis is preformed.
Kossiakoff and Sweet (2003) describe concept exploration and concept definition as phases in concept development where concept exploration entails the performance to meet the need in a feasible cost-effective approach while concept definition involve the key characteristics that balance cost, operational life, and capability. In concept exploration, different factors that determine how to handle a new system are explored with the main objective of identifying the feasible projects to develop.
During concept exploration, an analysis is performed on different approaches and alternatives which are deemed feasible, from which the best project is selected. During the concept definition phase, the system engineer defines the required specification for the system and specifies its architecture (Kossiakoff, & Sweet, 2003). It is during this phase that the necessary resources, components, and functions for the system are specified. Further, the analysis is implemented on different architectures and functions to achieve the system.
A crucial objective during concept definition involves making sure that one does not ignore any potential concept opportunities while in the concept exploration phase the objective involves setting up the system performance requirements and passing them to the concept definition stage. In concept exploration, a comparison of concepts as a system instead of individual functions is done while during concept definition, the system engineer compares the individual function at a time. Further, in concept exploration, system options are examined with subsystems with defined functions. Visualization is done for components only.
Therefore, the concepts of concept definition and concept exploration are different in that the concept exploration stage involves an analysis of the operational needs to attain the objectives of the operation. Concept definition, on the other hand, involves performance requirement that appropriate for the chosen system design (Kossiakoff, & Sweet, 2003). Concept definition contains functional models and validation testing for the chosen system. Concept exploration converts the operationally oriented view of the system resulting from the needs analysis phase into an engineering-oriented view suitable in the concept definition.
References
Kossiakoff, A., & Sweet, W. N. (2003). Systems engineering, principles and practice. John Wiley & Sons.
Leave a Reply