ENSE 622: Project Abstracts, Spring Semester, 2004
[ Project 1 ] : Augmented Cognition for Cockpit Design
[ Project 2 ] :
XML Schemas and Visual Modeling for Requirements Represenation
[ Project 3 ] :
Implied Scenario Analysis of Traffic Intersection Behavior
[ Project 4 ] : Dynamic Requirements Trade-off
[ Project 5 ] : Washington Metro System Safety Improvement
[ Project 6 ] :
Information Collection/Analysis for a Fishery Statistics System
[ Project 7 ] :
Modeling the Hubble Space Telescope Electrical Power Subsystem
[ Project 8 ] :
Analysis of Queuing Theory as a System
[ Project 9 ] :
Intelligent Climate Control System (IC2S)
[ Project 10 ] :
Modeling HVAC Control with LTSA
[ Project 11 ] :
Health Care Services Information Systems
Title: Augmented Cognition for Cockpit Design
Authors: Colby Raley and Latosha Marshall
Abstract : DARPA's effort in Augmented Cognition program will enable military systems to non-invasively measure the cognitive state of a user and execute mitigation strategies to alleviate work overload. The goal of the program is to increase the information processing capability of the human-computer closed-loop system, by making the human-computer symbiot more efficient than either component alone.
Currently, AugCog technology is being developed for use in four distinct platforms that challenge different aspects of cognition: working memory (processing simultaneous competing tasks), executive function (recalling contextual information), sensory input (exploiting multiple sensory channels for increased input capacity), and attention (prioritizing tasks). The current testing platforms are a computer-based command decision weapons environment (challenges working memory), an unmanned combat vehicle interface (challenges executive function), a combat vehicle challenges sensory input channels), and a mobile, integrated individual combat system (challenges attention).
Eventually, the AugCog technology should be able to reduce work overload of either of the four challenge areas or any combination of all four and be operational in any combat platform. For this project, we will examine the feasibility of modular design to accomplish this futuristic goal of combining these technologies. We will explore the possible inclusion of modules and universal components in various combat situations. The completion of a modular design for AugCog will enable its use in various applications and will make the implementation of this exciting technology much more feasible.
Title: XML Schemas and Visual Modeling for Requirements Represenation
Authors: Ron Henry
Abstract: Requirements can be linked to models using a simplified XML representation of some of the key UML diagrams: in particular use-case diagrams, class diagrams, and state diagrams. Guarded state transitions seem promising as a representation for one class of functional requirement. I have looked at XMI and concluded it is far too complex to be workable in the time available. Instead, I'll develop my own data model for the UML diagrams in question (Tibco already includes sample DTDs for some UML diagrams, which can serve as a starting point). This will enable subsequent experimentation with concepts from UML 2.0 that are not yet supported by affordable tools. It will not be interoperable with UML tools, but the important thing about UML from a research perspective is the model semantics, not the graphical representation. In my case study I will need to develop some UML diagrams using Poseidon or Visual Paradigm for illustration purposes, but these will have to be hand-translated into the improvised XML model.
Here is the plan:
Title: Implied Scenario Analysis of Traffic Intersection Behavior
Authors: Noosha Haghani and Maliheh Poorfarhani
Abstract: To determine whether we can find any Implied Scenarios using FSP and LTS modeling for the Traffic Intersection Project completed in an earlier semester. The hMSCs and bMSCs will be drawn using the LTSA 2.3 Tool with the MSC Plugin. These scenarios will be used to generate the FSP code that can be compiled into the LTS diagrams. These diagrams will then be composed (parallel composition) in order to see the entire architecture model. Once we have the entire architecture model, a test will be ran to determine whether the design has an implied scenarios, specifically any negative scenarios with catastrophic results.
Mini Project Abstract:
To generate sequence diagrams (hMSC and bMSC) that will create the FSP and LTS modeling for the One-way Bridge Example developed by Uchitel. The goal is to determine whether one can find any implied scenarios from the sequence diagrams that will alert us to the possible crash.
Title: Dynamic Requirements Trade-off
Authors: Fred Faber and Julie McNeil
Abstract: One major issue in requirements engineering is the trade-off analysis among system requirements. One form in which this analysis manifests itself is the selection of features to be added to a system; in such an instance well-defined constraints preclude the inclusion of all features. As such, the system designers must perform trade-off analysis among the available features in order to maximize the new system design.
A specific case of this issue is illustrated by a stakeholder meeting in which different parties with conflicting interests aim to select features that will be added to a system. For example, an electronics firm may hold a meeting with its marketing, sales, and engineering departments in order to determine what functionality to include in its new cell phone. In such a case, it is important to recognize and consider that each party may value the inclusion of a particular feature differently. This elevates the trade-off involved from an objective cost / objective trade-off to a more complex trade-off that must also include a feature's subjective desirability.
This project aims to address this issue by providing a tool to facilitate this complex trade-off analysis. Specifically, the tool will address feature selection in the context of conflicting interests among stakeholders of a system. As a goal, the tool will output a set of requirements that represent an optimal system design.
As input, the tool will receive a list of proposed features, modeled as functional requirements. All such requirements will be associated with a financial cost and a temporal cost. These costs are constrained by the total system cost and the total schedule allotted for the system. Also, all requirements are associated with a score that represents a particular stakeholder's desire to include that requirement. These rankings will be used to determine the importance of the inclusion of one requirement versus other requirements. Further, dependencies between requirements will also be considered. For example, the installation of a particular feature may lessen the cost associated with an additional feature; this association will be considered by the tool.
The requirements, the costs associated with each requirement, and the system constraints will be defined at the onset of the trade-off analysis. Once this is done, each stakeholder involved will rank the importance of each requirement. A weighted average of these rankings will then be calculated. Following, the tool will use a non-linear programming engine to determine an optimal set of requirements.. This will then be presented to the user
Specifically, the system will be implemented initially as a functional framework developed in Java. The framework will allow for the selection of a particular user interface through which to input requirement data (e.g. web interface, Java Swing interface). Accordingly, the framework will adjust its data storage medium (e.g. web ' RDB, Swing ' XML). The framework also will provide a choice of nonlinear solver engines (e.g. XPress SLP API, Excel Frontline Solver). Different output devices will also available, although manual graphing likely will be most the effective method.
Title: Washington Metro System Safety Improvement
Authors: Albert Anoubon Momo
Abstract : The Washington Metropolitan Area Transit Authority (WMATA) operates the second largest rail transit system in the United States. The (WMATA) was created in 1967 by an interstate pact to plan, develop, build, finance and operate a regional transportation system in the National Capital area. The WMATA Metrorail portion has 83 stations with 103 miles of track. The Metrorail consists of the subway, aerial and surface stations. The WMATA consists of subsystems that are large enough and complex enough to be considered systems.
Safety and security are a main concern for the Washington Metro System. The Washington Metro System, including the computerized control and information systems supporting the metro system, were designed to address safety issues and security issues and to ensure that the Metro system had adequate evacuation capabilities for the passengers. The computerized control and information systems are critical to providing safety and security, since they provide the following safety and security features through a Supervisory Control and Data Acquisition System (SCADA):
While the Washington Metro system has made significant safety improvements in the control and monitoring systems since the Shady Grove, MD train collision in 1996, events such as the September 11th terrorist attack have drawn attention to disaster preparedness and the ability of the Washington Metro system to manage a large-scale disaster.
The Washington DC Metro system does not have an adequate information system to manage emergencies or plan evacuation activities (an emergency management system). The Metro system has SCADA systems in place that provide control of train and rail systems and that provide systems monitoring capabilities. However, this system does not include linkages to evacuation plans, emergency exit routes, passenger data, or local emergency response teams.
The purpose of this project is to plan, analyze, and design an automated system to provide "real time" emergency management capabilities for the Washington DC Metro System. The case study will focus specifically on developing an information system to assist in Metro evacuation, emergency response coordination in the event of an emergency affecting the Metro system. This system will monitor train traffic, train locations, train speeds, train directions and estimated numbers of passengers and continuously compare train information to predetermined evacuation routes and provide real-time updates to the evacuation plans.
In scope items:
Title: Information Collection/Analysis for a Fishery Statistics System
Authors: Jon Eser and Noriaki Suzuki
Abstract : We aim to improve the Fishery Development Center's (FDC) statistics system for the Ministry of Agriculture in the nation of El Salvador. By collecting statistical information on the fish caught per year in El Salvador, inferences can be made about biological data such as the population of various species of fish, their maturity, their gender, and their size. After compiling the data provided by local offices and regional collectors, the Fishery Development Center (FDC) will analyze the data. Results from this study will go on to support an annual report published by the organization, recommendations to the national legislature for fishing restrictions, and installation of artificial reefs to act as sanctuaries for many fish. Moreover, data analysis will help to determine if modifications within the system in particular dealing with data collection will help to increase the future precision of data.
Currently, the system redesign project includes several UML type visualizations, which describe the structure and behavior of the redesigned information collection and analysis system. A CPLEX based trade off analysis was also performed, which aided in directing system design to an optimal state. Three ideas added to the project include:
This strategy will create an internally self consistent design to the system that with proper concept validation will ensure system success. By identifying all potential positive and negative scenarios within our system, necessary functions or structures that were deficient in the original design will be implemented and unnecessary or redundant design structures/behaviors may be effectively eliminated. Supplementing the automated scenario analysis with requirements development will further consolidate the system. During the process of stating requirements, further insight is achieved into additional needs in terms of system structure/behavior. Requirements must be stated and involved in the system design stage so that stakeholder goals may be realized. The third project step for the semester involves modifying the state chart view of system objects into a concurrent viewpoint this will aid in visualization of concurrent system behavior.
Title: Modeling the Hubble Space Telescope Electrical Power Subsystem
Author: Nzinga Tull
Abstract : This project is an extension of my class project from ENSE 621, "Modeling the Hubble Space Telescope Electrical Power Subsystem."
This semester will focus on developing requirements, designing, and performing trade-off analysis for software-controlled battery charging system. This will include flight software monitoring of all key power system parameters, management of battery charge rates, autonomous hardware re-configuration algorithms in response to on-board power system anomalies and automation of battery capacity checks.
Title : Analysis of Queuing Theory as a System
Authors: K. Alex Loe, Melody Djam, Elizabeth Lee
Abstract : The system we will be examining as a problem setting is a queuing system found in the checkout process in retail stores. We will characterize the system using use case scenarios. We will look at questions that come up in designing such a system by using simulations and optimization techniques. More specifically, we will look at factors such as the number of checkout stands required to support various numbers of customers and the costs associated by
Using these various tools and techniques, we will derive conclusions how to design the checkout queue system that will aid us in writing requirements and the resources required to design a system that will meet our requirements.
Title : Intelligent Climate Control System (IC2S)
Authors: Oliver Sadorra and Tim Sloane
Abstract : Typical climate control systems use a single thermostat to control the temperature of a home or workplace in a reactive manner. The intelligent climate control system (IC2S), on the other hand, will allow for different temperatures in different rooms or zones of the home or workplace. It will also act predicatively; it will use information from outside weather conditions, forecasts, as well as home characteristics to ensure the climate is to the owner's liking.
The IC2S will be designed to be modular; it will be broken up into six different modules:
The project for this semester will continue the design of the IC2S and will consist of two major components. First, a design structure matrix method will be used to determine the most efficient plan to make the individual modules. Second, a Labeled Transition System (LTS) will be designed for each module, and concurrent states will be defined between the modules; this allows for analysis of the concurrent behavior among the modules. Applying this analysis, undesirable behavior can then be isolated and eliminated.
Title : Modeling HVAC Control with LTSA
Author: Sriram, Monkompu K.
Abstract : he objective of this project is to use the LTSA program to model and analyze the Cascade Heating Ventillation and Air Conditioning (HVAC) system used in a large industrial project. The main equipment in the process are the Air-Handler and two Filters. The Air Handler supplies air into the chemical building where the neutralization of the toxic chemicals take place. The air cascades through the building from the outside peripheries progressively to the center of the building which is maintained more negative. Air is drawn out of the building by the two filters which consist of HEPA and charcoal filters where any of the toxic chemicals are filtered and captured. The HVAC system is controlled by a control system that is programmed to perform a complex set of logics for startup, operation and shutdown. The LTSA program will be used to model the system and run the analysis.
Title : Health Care Services Information Systems
Authors: Gokul Rathinasamy, Pampa Mondal
Abstract : The goal of this study is to develop a systems model that allows medical professionals to efficiently manage health care information. We would like to delineate and evolve this problem in system's engineering process using use cases, requirements, and models of system behavior, system structure, traceability and evaluation.
The study will help us devise a system to store patient's personal information, clinical documentation, and outcome measurement. The goal is to develop a seamless health care management system that will help to reduce administrative costs and improve patient care by converting paper-based patient records to electronic records.
The goals for this semester are as follows:
As projects and programmes become more and more complex, Requirement Analysis is becoming an increasingly important tool for any quality aware organisation. Requirement Analysis however is only as good as the analysis manager, the data and the system used to perform it
Key Benefits: (i) Customisable level of co! ntrol; (ii) Automated and Semi-Automated reporting capability that saves hours of personnel effort and provides reliable/impartial results; (iii) Easy to learn and quick to use systems available; (iv) Cost efficient personal service at any stage you requ! ire.
ENSE 621 Projects, Fall Semester, 2003.
[ Project 1 ] : MP3 Download System
[ Project 2 ] : Variable Message sign control and installation system
[ Project 3 ] : Health Care Management System (HCMS)
[ Project 4 ] : U-Scan Self Check-out System
[ Project 5 ] : General-Purpose Communcations System
[ Project 6 ] : Large Cascade HVAC System
[ Project 7 ] : Intelligent Home Climate Control System
[ Project 8 ] : Fishery Statistics System
[ Project 9 ] : The Cognitive Cockpit
[ Project 10 ] :
WPC3 Instrunment Design for the Hubble Space Telescope
[ Project 11 ] :
Improvements to the Washington DC Metro System
[ Project 12 ] :
A Systems-Centric Approach to Telecommunications Planning.
[ Project 13 ] :
Modeling the Hubble Space Telescope Electrical Power Subsystem
[ Project 14 ] :
Terrestrial Visualization Satellite (TVS)
Title : MP3 Download System
Authors: K. Alex Loe, Melody Djam, Elizabeth Lee
Abstract : Every day thousands of MP3 files are illegally traded on the Internet via online networks. The networks allow users to download audio files from other users at no cost. Although this system appears advantageous to the users who obtain music for free, downloading this music is essentially stealing from the music industry and the artists themselves. Recently, and at the request of music industry members, law enforcement entities have begun to press charges against MP3 file sharers.
The purpose of this project is to use systems engineering principles to develop a new MP3 exchange system. The new system will buy the music files from the individuals who own the music rights and sell them at a small fee to the system users. This system will allow the music industry to profit on the sale of their music. Prices for each music file will remain low because the system will also support advertisements to acquire additional revenue. Why would anyone pay a fee to use the new system when they could acquire the same files elsewhere for free? The price of downloading music using the new system will be so minimal that the small price will be more desirable than risking legal action.
We will continue to define our requirements, and utilize concepts learned in class to explore areas such as alternatives analysis, optimization on system response or profit, and trade off.
Title : Variable Message Sign Control and Installation System
Authors: Maliheh Poorfarhani, Imane Adouani
Abstract : Variable Message Systems (VMSs) display different messages at different times. This kind of system is usually used on highways, and construction locations to display weather conditions, emergency news and others. Variable message signs are controlled by operators at remote centers. They could also be controlled by more than one operator at different times. And at the same time, an operator could control more than one sign.
Title : Health Care Management System (HCMS)
Authors: Gokul Rathinasamy, Pampa Mondal
Abstract : The purpose of this study is to develop a systems model that allows medical professionals to efficiently manage health care information. We would like to delineate and evolve this problem in system's engineering process using use cases, requirements, and models of system behavior, system structure, traceability and evaluation.
The study will help us devise a system to store patient^Òs personal information, clinical documentation, and outcome measurement. The goal is to develop a seamless health care management system that will help to reduce administrative costs and improve patient care by converting paper-based patient records to electronic records.
Purpose of this system (why we need this system):
Title: U-Scan Self Check-out System
Authors: Julie McNeil, Fred Faber
Abstract : This system is used in groceries so that customers can scan products and pay for them with minimal cashier assistance.
Title: General-Purpose Communcations System
Author: Kevin Fogarty
Abstract : The goal of my project was to design a communications system that could be used by any corporation. The system was designed to provide voice, data, and video communications on a single network (infrastructure). I would like to continue to develop the system by adding requirements/capabilities and performing additional trade-off analysis.
Title: Large Cascade HVAC System
Author: Sam Sriram
Abstract : This project is to analyze a large cascade HVAC system we built in our chemical demil plant here. We neutralize highly toxic chemical agents inside a special building. This HVAC system provides 100% outside air and there is a progressive reduction in the air pressure as the air is moved from the outer side of the building towards the most toxic area and then finally drawn out through carbon filters. All the logics and controls are implemented in a Foxboro Distributed Control System. I did all my sketches and diagrams using MS Excel. I tried to use all the different tools that were taught to us. I used the AHP method to do Trade-off analysis.
Title :
Intelligent Home Climate Control System
Authors: Jeff Green (Fall 2003), Oliver Sadorra (Spring 2004), and Tim Sloane
Abstract : Typical climate control systems use a single thermostat to control the temperature of the home and work in a reactive manner. The intelligent system will allow for different temperatures in different rooms or zones of the home. It will also act predicatively, using information about the outside weather conditions, forecasts, and home characteristics, to ensure the climate is to the owner's liking.
The system will operate using separate temperature controls and sensors in each room or zone of the home, all connected to a central control system. The sensors in each room will monitor the temperature and humidity. Additional sensor systems will monitor the use of heat generating appliances such as stoves and ovens, the outside temperature and humidity, sunlight, wind speed, and precipitation. The central control system will also monitor near term weather forecasts.
Title: Fishery Statistics System
Authors: Jon Eser and Noriaki Suzuki
Abstract : We aim to improve the Fishery Development Center's (FDC) statistics system for the Ministry of Agriculture in the nation of El Salvador. By collecting statistical information on the fish caught per year in El Salvador, inferences can be made about biological data such as the population of various species of fish, their maturity, their gender, and their size. After compiling the data provided by local offices and regional collectors, the Fishery Development Center (FDC) will analyze the data. Results from this study will go on to support an annual report published by the organization, recommendations to the national legislature for fishing restrictions, and installation of artificial reefs to act as sanctuaries for many fish. Moreover, data analysis will help to determine if modifications within the system in particular dealing with data collection will help to increase the future precision of data.
Problems.
Goals.
Title: Augmented Cognition for Cockpit Design
Authors: Colby Raley and Latosha Marshall
Abstract : The Augmented Cognition (AugCog) program is developing: (1) new technologies to noninvasively measure a human's cognitive state, and (2) closed-loop systems that will use cognitive state information to adapt computers to humans' needs. This program was initiated because of the continuing excess of information that people face every day. Not only is there too much valuable and useful information than can reasonably be digested, there is also an ever-growing expanse of information that is useless either because of its nature or because of who gets the information and when they get it. The AugCog program will dramatically increase the ratio of good information to "bad" information and will enable end users to do better work, more of it, and do it faster.
Currently, AugCog technology is being developed for use in four distinct platforms that challenge different aspects of cognition: working memory (processing simultaneous competing tasks), executive function (recalling contextual information), sensory input (exploiting multiple sensory channels for increased input capacity), and attention (prioritizing tasks). Eventually, the technology should applicable to any combination of these cognitive challenges (cognitive bottlenecks) - even a combination of all four. The current testing platforms are a computer-based command decision weapons environment (challenges working memory), an unmanned combat vehicle interface (challenges executive function), a combat vehicle (challenges sensory input channels), and a mobile, integrated individual combat system (challenges attention). The predicted platform for the next phase of the program is the cockpit, as it challenges all of these aspects of cognition together.
The initial systems engineering challenges for the "Cognitive Cockpit" (phase three of AugCog) include:
Title:
WPC3 Instrument Design for the Hubble Space Telescope
Authors: Ron Henry and Rashad Moore (in ENSE 621)
Abstract : I selected the design of WFC3, a state-of-the-art science instrument being developed for the Hubble Space Telescope. Work on WFC3 began in 1998, and it is now completing its environmental testing. WFC3 was to have been installed on the HST servicing mission known as SM4. As you may have heard, NASA recently decided to cancel that mission, so the fate of WFC3 and its companion instrument (COS) are now uncertain. NASA has held out some hope that these instruments may be used for a future space science mission. At any rate, the project was done based on the "as-designed" WFC3.
WFC3 is a camera with two optical channels, a near-ultraviolet/visible channel (called the UVIS channel) and a near-infrared channel (the IR channel). Observers will use the system to prepare observations containing exposures to execute on the camera. For each exposure an observer will specify the optical channel to use, a filter to put in place to restrict the spectral bandpass of the incident light, and the exposure duration. Each channel contains an electronic detector, which will convert detected photons into electronic signals and produce a digital array of accumulated photon counts. There are also two types of calibration exposures that observers may specify: a ³dark² exposure during which the detector is shielded from external light, and an exposure with an internal calibration lamp that is used to provide a uniform illumination across the detector. The instrument has an internal data buffer that is used for primary storage of recorded images. The system will use this buffer for temporary storage to improve observing efficiency, and will transfer data from the data buffer to the HST data recorder for secondary storage.
In the previous semester, Rashad Moore and I modeled the WFC3 system at a high level, focusing on the operations of the instrument. This system comprises the instrument hardware, the flight software to operate it, and the instrument-specific ground software needed to prepare observations and process the data. Since WFC3 was to be integrated into the existing HST system, it was necessary to describe the interfaces with that system but not the functionality to be provided through existing infrastructure.
The first phase of the project involved UML modeling. We used a free version of Poseidon as our tool. I found this buggy and not very satisfactory, and I'm looking for an alternative that I can run on a Mac (Visual Paradigm looks worth investigating). Poseidon did provide support for all the standard UML diagrams. We began by defining our top-level system actors and identifying a set of about 12 system-level use cases. The relationships between use cases and actors were modeled on a use-case diagram. A domain model was developed through a series of class diagrams with attributes and operations. The use cases were written up as text and then modeled as activity diagrams. We had some discussions about going further to sequence diagrams, but this seemed an unnecessary level of detail for the modeling we were doing and we didn't have time.
The final step in the modeling was to develop a set of requirements that were mapped to both the system structure (classes, attributes and operations) and system behavior (use cases). Dr. Baras called this a traceability matrix. In our case the requirements were taken from the original requirements document for WFC3, called a CEI spec, which was available on the Web and contained about 300 requirements. About 60 of these were identified as relevant to operations and were included for the mapping.
The second phase of the project was developing an analytic model for tradeoff analysis. A small set of design variables were introduced that represented design options early in the project (such as detector selection). A design alternative corresponds to a particular combination of these variables. Alternatives were evaluated with respect to two performance metrics and a cost metric. The performance metrics were "science productivity" and "science flexibility." These were defined using a nonlinear model. In the case of science productivity, a good analytical framework was available based on signal-to-noise theory. For cost evaluation, we used a linear model based on plausible but fictitious data. A set of constraints were also defined. The only nontrivial constraint involved data volume, which could not exceed the capacity of the communications system used to downlink HST data.
I used the Excel Solver utility, which handles nonlinear models, to perform the optimization. Rather than trying to combine objectives, I used the procedure recommended by Dr. Baras of treating two of the objectives (flexibility and cost) as constraints and solving for the third (science productivity). By systematically tightening or relaxing the constraints, a series of tradeoff curves was developed that gave the maximum science productivity as a function of minimum flexibility and maximum cost. A total of 33 combinations of these constraints were evaluated. For each set of constraint values, the optimizer returned the set of design variables that corresponded to maximum science productivity. Analysis of the results showed that the behavior appeared reasonable.
Title: Improvements to the Washington DC Metro System
Authors: Albert Anoubon Momo and Vonderlear Fields (in ENSE 621).
Abstract : The purpose of this case study is to apply the fundamentals of systems engineering to improve the Washington DC Metro System. The case study will focus specifically on improving features of the equipment, hardware and software used within the system to enhance the safety of the operators, and equipments and communities that border the Metro System."
Title: A Systems-Centric Approach to Telecommunications Planning
Authors: Chad A. Rivera
Abstract : Given a geographic region, create a telecommunications infrastructure plan that will provide a reliabe communications channel from the customer to the backbone.
Title: Modeling the Hubble Space Telescope Electrical Power Subsystem
Authors: Nzinga Tull and Adaeze Okorie (in ENSE 621)
Abstract : he Hubble Space Telescope (HST) operated through a program coordinated by the National Aeronautics and Space Administration (NASA) and the European Space Agency. HST was launched in 1990 as NASA first long-term, space-based science observatory. Since HST is positioned in low-earth-orbit (375 miles), its vision into space is not impeded by the earth's blurring atmosphere. HST has an orbital period of 96 minutes (31 minutes in orbit day and 65 minutes in orbit night). With high-quality pointing precision, powerful optics, and premier science instruments, HST has been able 0to provide images of more celestial forms that are far clearer and far more detailed than any ground-based observatory. NASA has planned and executed several "servicing missions" since the telescope's launch during which astronauts repair or replace aging science instruments and vehicle support equipment to prolong mission life and increase science capabilities.
The Electrical Power Subsystem (EPS) is a critical HST subsystem in that it provides and regulates the power required to operate the various optical and science instruments as well as other fundamental vehicle support functions (e.g., data management and distribution, vehicle slew control). The primary components of the system include: solar panel assemblies, batteries, power distribution unit, k-relays, charge current controllers (CCCs):
The HST EPS is a very complicated, multi-component subsystem. Power system performance is affected by many non-linear attributes (vehicle load, solar season flux, battery degradation rate, solar array degradation rates, ..etc) and is evaluated based on several competing and criteria. For this project effort, we focused on developing an object-oriented, system-level view of the hardware battery charge control scheme using the CCCs.
Title: Terrestrial Visualization Satellite (TVS)
Authors: Noosha Haghani and Trevor Vaughan (in ENSE 621)
Abstract : The purpose of this project is to model a simple satellite that contains a camera (instrument), which can take pictures of modern-day activities on Earth (i.e. traffic patterns). The satellite shall receive commands from the ground system and transmit telemetry that includes status and instrument data/images captured by the camera. In order to minimize cost, this instrument can fly as a secondary payload on a larger mission. This lowers the amount of hardware and real estate allowed to support the instrument; thus the camera controller hardware will be located in the Command and Data Handling sub-system. However, the instrument can fly separately as its own mission.
A satellite has at least three main sub-systems
This project will focus on the communications aspects of the Command and Data Handling sub-system when modeling the behavior of the system. Use cases, requirements, structural and behavioral models will be used to demonstrate this is a systems engineering framework. Trade-off analysis to minimize cost and maximize data throughput to ground will also be completed.