A development of logistics management models for the Space Transportation System

A new analytic queueing approach was described which relates stockage levels, repair level decisions, and the project network schedule of prelaunch operations directly to the probability distribution of the space transportation system launch delay. Finite source population and limited repair capability were additional factors included in this logistics management model developed specifically for STS maintenance requirements. Data presently available to support logistics decisions were based on a comparability study of heavy aircraft components. A two-phase program is recommended by which NASA would implement an integrated data collection system, assemble logistics data from previous STS flights, revise extant logistics planning and resource requirement parameters using Bayes-Lin techniques, and adjust for uncertainty surrounding logistics systems performance parameters. The implementation of these recommendations can be expected to deliver more cost-effective logistics support

Allotment of aircraft spare parts using genetic algorithms

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

An Overview of Sustainability of Transportation Systems: A Quality Oriented Approach

Sustainable transportation system-structure is crucial for the population of mega countries. This system aims to provide better and more qualified alternatives of supplying specific and household requirements while decreasing the ecological and social effects of present mobility applications. The objective of this study is to investigate the risk factors of substantial transportation arrangement in the ordinary railway system and highway transportations. According to the basic issue, which is indicated in this study, the purpose of this research is to define improvements, which can support flexible transportation and control the traffic jams and properties of the proposed structure for the populations in the system. This research supports a conventional review for transportation systems in environmental conditions, pollutions, and forestlands. To address this topic, a quality-oriented implementation was applied to evaluate the failure modes and effect analysis and the significant factors were determined via Pareto Analysis to control and prevent the probable failures in the transportations systems

An evaluation of the stormwater quality performance of catch basin filter/inserts

With the impending implementation of EPA\u27s National Pollutant Discharge EliminationSystem (NPDES) Phase 11 regulations, the demand for innovative and effective means of dealing with point and non-point source pollution is and will continue growing. Catch Basin filters have been recently introduced as an alternative type of stormwater qualityBest Management Practice (BMP). With Phase 11 requirements on the horizon, numerous companies have begun manufacturing and selling unique designs of catch basin insert/filters. This thesis will present a performance analysis of these innovative water quality BMPs to determine if all filter models are practical for all hydrologic and hydraulic conditions. The study will summarize what the filters are and what they do, what filters are being manufactured and by whom, and what level of performance has been observed by selected municipalities who are using the inserts. Also summarized is a field study on the AquaShield™ catch basin filter that was conducted to determine the expected pollutant removal efficiency and overall performance in a highly urban setting. The Primary purpose of this thesis is to evaluate the overall performance of catch basin insert/filters and develop recommendations and guidelines for municipalities to use when considering the installation of a this type of water quality BMP

Simulated Multi-Echelon Readiness-Based Inventory Leveling with Lateral Resupply

For the past fifty years, U.S. Air Force reparable inventory has been allocated based on an analytic model developed by Dr. Craig C. Sherbrooke. Although versions of his model can be implemented easily with the help of a computer, the analytic approach fundamentally lacks the flexibility to address numerous logistics issues. This body of research will offer a novel alternative approach that will enable researchers to investigate currently unsolved logistics problems such as quantifying the benefits of lateral resupply

Alternative water sources for urban consumers – A novel technology for the City of Cape Town urban resident

South Africa is classified as being the 30th driest country in the world and is regarded as a water scarce country. However, for the urban residents of the City of Cape Town, the ability to reduce their municipal water consumption through initiatives, other than simply using less water, is limited. Hence, there is a need for affordable, simple and compact technical solutions which allow urban populations residing in high density developments to make use of alternative sources of water, specifically greywater, to reduce their municipal water demand. Existing commercial technologies were considered, together with the socio-economic and technical constraints of an illustrative middle-income urban household in the City of Cape Town (CoCT). It was found that each commercial technology considered satisfied some, but not all, constraints characteristic of the household. For instance, the treatment device may produce treated water of a high quality. However, it may not be financially feasible for the consumer. Of the commercial technologies considered, there is no single commercial technology which can offer a complete solution within the socio-economic and technical constraints of the household. For this reason, the opportunity exists to produce an innovative technical solution. The proposed greywater treatment device consists of four cylindrical chambers in a vertical arrangement. Raw greywater enters the top chamber and treated greywater is extracted from the bottom chamber forming the base. The treatment processes undergone as the greywater flows through the treatment device include, in the following order, pre-filtration, biological treatment (Activated Sludge), clarification, filtration and disinfection. The process is driven by a combination of gravity and electrical energy. The proposed design is constructed using readily available materials and components. It is modular in its construction, allowing for easy maintenance, assembly and an increase in design flexibility. Evaluating the design against the same evaluation criteria stipulated for the existing commercial technologies showed that the proposed design may be an appropriate solution for the illustrative middle-income household within the City of Cape Town and is a novel technical solution

NASA System Safety Handbook

System safety assessment is defined in NPR 8715.3C, NASA General Safety Program Requirements as a disciplined, systematic approach to the analysis of risks resulting from hazards that can affect humans, the environment, and mission assets. Achievement of the highest practicable degree of system safety is one of NASA's highest priorities. Traditionally, system safety assessment at NASA and elsewhere has focused on the application of a set of safety analysis tools to identify safety risks and formulate effective controls.1 Familiar tools used for this purpose include various forms of hazard analyses, failure modes and effects analyses, and probabilistic safety assessment (commonly also referred to as probabilistic risk assessment (PRA)). In the past, it has been assumed that to show that a system is safe, it is sufficient to provide assurance that the process for identifying the hazards has been as comprehensive as possible and that each identified hazard has one or more associated controls. The NASA Aerospace Safety Advisory Panel (ASAP) has made several statements in its annual reports supporting a more holistic approach. In 2006, it recommended that "... a comprehensive risk assessment, communication and acceptance process be implemented to ensure that overall launch risk is considered in an integrated and consistent manner." In 2009, it advocated for "... a process for using a risk-informed design approach to produce a design that is optimally and sufficiently safe." As a rationale for the latter advocacy, it stated that "... the ASAP applauds switching to a performance-based approach because it emphasizes early risk identification to guide designs, thus enabling creative design approaches that might be more efficient, safer, or both." For purposes of this preface, it is worth mentioning three areas where the handbook emphasizes a more holistic type of thinking. First, the handbook takes the position that it is important to not just focus on risk on an individual basis but to consider measures of aggregate safety risk and to ensure wherever possible that there be quantitative measures for evaluating how effective the controls are in reducing these aggregate risks. The term aggregate risk, when used in this handbook, refers to the accumulation of risks from individual scenarios that lead to a shortfall in safety performance at a high level: e.g., an excessively high probability of loss of crew, loss of mission, planetary contamination, etc. Without aggregated quantitative measures such as these, it is not reasonable to expect that safety has been optimized with respect to other technical and programmatic objectives. At the same time, it is fully recognized that not all sources of risk are amenable to precise quantitative analysis and that the use of qualitative approaches and bounding estimates may be appropriate for those risk sources. Second, the handbook stresses the necessity of developing confidence that the controls derived for the purpose of achieving system safety not only handle risks that have been identified and properly characterized but also provide a general, more holistic means for protecting against unidentified or uncharacterized risks. For example, while it is not possible to be assured that all credible causes of risk have been identified, there are defenses that can provide protection against broad categories of risks and thereby increase the chances that individual causes are contained. Third, the handbook strives at all times to treat uncertainties as an integral aspect of risk and as a part of making decisions. The term "uncertainty" here does not refer to an actuarial type of data analysis, but rather to a characterization of our state of knowledge regarding results from logical and physical models that approximate reality. Uncertainty analysis finds how the output parameters of the models are related to plausible variations in the input parameters and in the modeling assumptions. The evaluation of unrtainties represents a method of probabilistic thinking wherein the analyst and decision makers recognize possible outcomes other than the outcome perceived to be "most likely." Without this type of analysis, it is not possible to determine the worth of an analysis product as a basis for making decisions related to safety and mission success. In line with these considerations the handbook does not take a hazard-analysis-centric approach to system safety. Hazard analysis remains a useful tool to facilitate brainstorming but does not substitute for a more holistic approach geared to a comprehensive identification and understanding of individual risk issues and their contributions to aggregate safety risks. The handbook strives to emphasize the importance of identifying the most critical scenarios that contribute to the risk of not meeting the agreed-upon safety objectives and requirements using all appropriate tools (including but not limited to hazard analysis). Thereafter, emphasis shifts to identifying the risk drivers that cause these scenarios to be critical and ensuring that there are controls directed toward preventing or mitigating the risk drivers. To address these and other areas, the handbook advocates a proactive, analytic-deliberative, risk-informed approach to system safety, enabling the integration of system safety activities with systems engineering and risk management processes. It emphasizes how one can systematically provide the necessary evidence to substantiate the claim that a system is safe to within an acceptable risk tolerance, and that safety has been achieved in a cost-effective manner. The methodology discussed in this handbook is part of a systems engineering process and is intended to be integral to the system safety practices being conducted by the NASA safety and mission assurance and systems engineering organizations. The handbook posits that to conclude that a system is adequately safe, it is necessary to consider a set of safety claims that derive from the safety objectives of the organization. The safety claims are developed from a hierarchy of safety objectives and are therefore hierarchical themselves. Assurance that all the claims are true within acceptable risk tolerance limits implies that all of the safety objectives have been satisfied, and therefore that the system is safe. The acceptable risk tolerance limits are provided by the authority who must make the decision whether or not to proceed to the next step in the life cycle. These tolerances are therefore referred to as the decision maker's risk tolerances. In general, the safety claims address two fundamental facets of safety: 1) whether required safety thresholds or goals have been achieved, and 2) whether the safety risk is as low as possible within reasonable impacts on cost, schedule, and performance. The latter facet includes consideration of controls that are collective in nature (i.e., apply generically to broad categories of risks) and thereby provide protection against unidentified or uncharacterized risks

Small business audit manual, Volume 1

https://egrove.olemiss.edu/aicpa_guides/2180/thumbnail.jp

TRIAD - A preliminary design of an earth resources survey system Needs analysis supplement

Social factors in design of operational earth resources survey syste