SEARCH · Engineering Papers

Results for “Requirements”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 451 records · Page 25

All sources NASA NTRS DOE OSTI

DOE OSTI2025

Requirements Framework for Cyber-Informed Engineering

The existing requirements frameworks or models cater to the existing practices. However, they fall short in directly using them for Cyber informed engineering. Therefore, this paper develops and presents a comprehensive framework that can be used for Cyber informed Engineering during the requirements phase. We describe the existing requirements process and models, then develop a requirements framework for cyber informed engineering.

97 MATHEMATICS AND COMPUTING↗

NASA NTRS2001

Requirements management at NASA

Requirements have always been acknowledged as the backbone of any system. However, in many past development efforts, requirements were paid little heed. At NASA, in recent years, the hue and cry for project development has been "Faster, Better, Cheaper and Safer". This has impacted the way we develop software; it has increased the risks to quality, safety and reliability. At NASA, the Software Assurance Technology Center (SATC) is working with projects to emphasize the criticality of requirements throughout development, not just in the initial phases. This emphasis is on requirements relationship to all aspects of quality, including reliability and safety. In this presentation, we will look at some of these relationships through the eyes of quality.

Requirement management↗

NASA NTRS2014

Facility Systems, Ground Support Systems, and Ground Support Equipment General Design Requirements

KSC-DE-512-SM establishes overall requirements and best design practices to be used at the John F. Kennedy Space Center (KSC) for the development of ground systems (GS) in support of operations at launch, landing, and retrieval sites. These requirements apply to the design and development of hardware and software for ground support equipment (GSE), ground support systems (GSS), and facility ground support systems (F-GSS) used to support the KSC mission for transportation, receiving, handling, assembly, test, checkout, servicing, and launch of space vehicles and payloads and selected flight hardware items for retrieval. This standards manual supplements NASA-STD-5005 by including KSC-site-specific and local environment requirements. These requirements and practices are optional for equipment used at manufacturing, development, and test sites.

Ground Support Systems↗

NASA NTRS2017

Requirement Development Process and Tools

Requirements capture the system-level capabilities in a set of complete, necessary, clear, attainable, traceable, and verifiable statements of need. Requirements should not be unduly restrictive, but should set limits that eliminate items outside the boundaries drawn, encourage competition (or alternatives), and capture source and reason of requirement. If it is not needed by the customer, it is not a requirement. They establish the verification methods that will lead to product acceptance. These must be reproducible assessment methods.

Tools↗

NASA NTRSDate not supplied

From Requirements to Autonomous Flight: An Overview of the Monitoring ICAROUS Project

The Independent Configurable Architecture for Reliable Operations of Unmanned Systems(ICAROUS) is a software architecture incorporating a set of algorithms to enable autonomous operations of unmanned aircraft applications. This paper provides an overview of Monitoring ICAROUS, a project whose objective is to provide a formal approach to generating runtime monitors for autonomous systems from requirements written in a structured natural language. This approach integrates FRET, a formal requirement elicitation and authoring tool, and Copilot, a runtime verification framework. FRET is used to specify formal requirements in structured natural language. These requirements are translated into temporal logic formulae. Copilot is then used to generate executable runtime monitors from these temporal logic specifications. The generated monitors are directly integrated into ICAROUS to perform runtime verification during flight.

Formal Methods↗

NASA NTRSDate not supplied

NASA Orbital Debris Mitigation Requirements Applied to Batteries

This presentation reviews the current state of NASA orbital debris mitigation requirements with respect to spacecraft batteries. NASA requirements address the probability of accidental explosion during and after mission operations, and probability of human casualty resulting from reentry. Excluding post-mission explosion, these probabilities must be evaluated against quantitative limits. Reentry demisability models provide the quantitative results to assess compliance with the casualty threshold. Some projects show compliance with the explosion requirement using manufacturers’ stated component or assembly reliabilities, while others cite similarity with past accepted projects. With the required threshold included in the USG ODMSP, NASA encourages the use of – and seeks – standardized methods to help quantify the probability of accidental explosion.

Batteries↗

NASA NTRSDate not supplied

Monitoring ICAROUS: From Requirements to Autonomous Flight

The Independent Configurable Architecture for Reliable Operations of Unmanned Systems (ICAROUS) is a software architecture incorporating a set of algorithms to enable autonomous operations of unmanned aircraft applications. This paper provides an overview of Monitoring ICAROUS, a project whose objective is to provide a formal approach to generating runtime monitors for autonomous systems from requirements written in a structured natural language. This approach integrates FRET, a formal requirement elicitation and authoring tool, and Copilot, a runtime verification framework. FRET is used to specify formal requirements in structured natural language. These requirements are translated into temporal logic formulae. Copilot is then used to generate executable runtime monitors from these temporal logic specifications. The generated monitors are directly integrated into ICAROUS to perform runtime verification during flight.

Formal Methods↗

NASA NTRSDate not supplied

Structural Requirements for Design and Analysis of 25% Scale Subsonic Single Aft Engine (SUSAN) Research Aircraft

The purpose of this paper is to define a set of structural requirements which can be used for conceptual design studies of the Subsonic Single Aft eNgine (SUSAN) aircraft and the early design phases of a quarter scale flight research aircraft. SUSAN presents an architecture for a subsonic regional jet transport aircraft coupling a single turbofan engine to an electrified aircraft propulsion system (EAP). Presented within this paper are a consolidated set of requirements drawn from NASA, FAA (FAR), and non-government structural standards with a focus on loads. An example application of the breakout load tables and the approach for applying existing standards to those configurations is presented for the SUSAN 25% flight research vehicle. Positioning of the turbofan, electric engines, battery and the requirement for the 25% vehicle to be shippable in a cargo box are atypical structural design requirements. Particular focus is given to the primary aircraft structural elements such as the engine/tail mount, fuselage structure, and wing structure.

structures↗

NASA NTRSDate not supplied

Structural Requirements for Design and Analysis of 25% Scale Subsonic Single Aft Engine (SUSAN) Research Aircraft

Structures↗

DOE OSTI2016

RELAP-7 Code Assessment Plan and Requirement Traceability Matrix

The RELAP-7, a safety analysis code for nuclear reactor system, is under development at Idaho National Laboratory (INL). Overall, the code development is directed towards leveraging the advancements in computer science technology, numerical solution methods and physical models over the last decades. Recently, INL has also been putting an effort to establish the code assessment plan, which aims to ensure an improved final product quality through the RELAP-7 development process. The ultimate goal of this plan is to propose a suitable way to systematically assess the wide range of software requirements for RELAP-7, including the software design, user interface, and technical requirements, etc. To this end, we first survey the literature (i.e., international/domestic reports, research articles) addressing the desirable features generally required for advanced nuclear system safety analysis codes. In addition, the V&V (verification and validation) efforts as well as the legacy issues of several recently-developed codes (e.g., RELAP5-3D, TRACE V5.0) are investigated. Lastly, this paper outlines the Requirement Traceability Matrix (RTM) for RELAP-7 which can be used to systematically evaluate and identify the code development process and its present capability.

42 ENGINEERING↗

NASA NTRS1996

My-Star: A Methodology and System for Tracing and Analyzing Requirements

This paper describes a methodology developed at the Jet Propulsion Laboratory (JPL), and designed for the process of requirements engineering and management. MY-STAR provides techniques for specifying, refining, allocating, baselining,sharing, changing, storing, and reporting on requirements and requirements metrics.

MY-STAR requirements engineering requirements mana↗

DOE OSTI2024

Formally Verified ZTA Requirements for OT/ICS Environments with Isabelle/HOL

The clean energy transformation includes the integration of distributed energy resources with the power grid, which has led to a substantial increase in the complexity of power grids infrastructure and the underlying operational technology environment. Power grids infrastructure represents an operational technology environment that has become a system of systems, integrating heterogeneous devices which are both software-and hardware-intensive; as a result, there are increasing demands to exploit advances in the commodity of software-hardware infrastructures to improve energy systems requirements such as cybersecurity and resilience. In such a setting, system requirements at different levels mix, which leads to vulnerabilities and undesirable outcomes. The use of formal methods to characterize and prove system requirements removes ambiguity, increases automation, and provides high levels of assurance and reliability. In this paper, we contribute a methodology and a framework for the system-level verification of zero trust architecture requirements in operational technology environments. We define a formal specification for the core functionalities of operational technology environments, the corresponding invariants, and security proofs. Of particular note is our modular approach for the formal verification of asynchronous interactions in operational technology environments. The formal specification and the proofs have been mechanized using the interactive theorem proving environment Isabelle/HOL.

formal methods↗

DOE OSTI2014

PCDH10 is required for the tumorigenicity of glioblastoma cells

Highlights: • PCDH10 is required for the proliferation, survival and self-renewal of glioblastoma cells. • PCDH10 is required for glioblastoma cell migration and invasion. • PCDH10 is required for the tumorigenicity of glioblastoma cells. • PCDH10 may be a promising target for the therapy of glioblastoma. - Abstract: Protocadherin10 (PCDH10)/OL-protocadherin is a cadherin-related transmembrane protein that has multiple roles in the brain, including facilitating specific cell–cell connections, cell migration and axon guidance. It has recently been reported that PCDH10 functions as a tumor suppressor and that its overexpression inhibits proliferation or invasion of multiple tumor cells. However, the function of PCDH10 in glioblastoma cells has not been elucidated. In contrast to previous reports on other tumors, we show here that suppression of the expression of PCDH10 by RNA interference (RNAi) induces the growth arrest and apoptosis of glioblastoma cells in vitro. Furthermore, we demonstrate that knockdown of PCDH10 inhibits the growth of glioblastoma cells xenografted into immunocompromised mice. These results suggest that PCDH10 is required for the proliferation and tumorigenicity of glioblastoma cells. We speculate that PCDH10 may be a promising target for the therapy of glioblastoma.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2018

Structural requirement of the hydrophobic region of the Bordetella pertussis CyaA-hemolysin for functional association with CyaC-acyltransferase in toxin acylation

Highlights: • Acylation of CyaA-Hly by CyaC-acyltransferase requires AR-acylation and HP-hydrophobic regions, hence hemolysis activation. • ∼100-kDa AR-containing CyaA-RTX lacking HP cannot be acylated by functional CyaC, thus hemolytically inactive. • ∼70-kDa hemolytically inactive-CyaA-HP/BI containing both AR and HP could interact with co-expressed CyaC. • ∼20-kDa CyaA-HP comprising α1-α5 potentially interacted with CyaC via multiple H-bonding and ionic interactions. • HP is required for not only membrane-pore formation but also CyaC-association, hence toxin acylation. Previously, we demonstrated that the ∼130-kDa CyaA-hemolysin (CyaA-Hly, Met{sup 482}-Arg{sup 1706}) from Bordetella pertussis was palmitoylated at Lys{sup 983} when co-expressed with CyaC-acyltransferase in Escherichia coli, and thus activated its hemolytic activity. Here, further investigation on a possible requirement of the N-terminal hydrophobic region (HP, Met{sup 482}-Leu{sup 750}) for toxin acylation was performed. The ∼100-kDa RTX (Repeat-in-ToXin) fragment (CyaA-RTX, Ala{sup 751}-Arg{sup 1706}) containing the Lys{sup 983}-acylation region (AR, Ala{sup 751}-Gln{sup 1000}), but lacking HP, was co-produced with CyaC in E. coli. Hemolysis assay indicated that CyaA-RTX showed no hemolytic activity. Additionally, MALDI-TOF/MS and LC-MS/MS analyses confirmed that CyaA-RTX was non-acylated, although the co-expressed CyaC-acyltransferase was able to hydrolyze its chromogenic substrate−p-nitrophenyl palmitate and acylate CyaA-Hly to become hemolytically active. Unlike CyaA-RTX, the ∼70-kDa His-tagged CyaA-HP/BI fragment which is hemolytically inactive and contains both HP and AR was constantly co-eluted with CyaC during IMAC-purification as the presence of CyaC was verified by Western blotting. Such potential interactions between the two proteins were also revealed by semi-native PAGE. Moreover, structural analysis via electrostatic potential calculations and molecular docking suggested that CyaA-HP comprising α1-α5 (Leu{sup 500}-Val{sup 698}) can interact with CyaC through several hydrogen and ionic bonds formed between their opposite electrostatic surfaces. Overall, our results demonstrated that the HP region of CyaA-Hly is conceivably required for not only membrane-pore formation but also functional association with CyaC-acyltransferase, and hence effective palmitoylation at Lys{sup 983}.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2018

Both the N- and C- terminal regions of the Chlamydial inclusion protein D (IncD) are required for interaction with the pleckstrin homology domain of the ceramide transport protein CERT

Highlights: • Both the N- and C-termini of IncD are required for the CERT-IncD interaction. • IncD residues essential for the binding to CERT are conserved among Chlamydiaces. • IncD forms multiple oligomers composed of a dimeric unit. Chlamydia trachomatis is an obligate intracellular bacterium that replicates within a membranous compartment, the inclusion, in host cells. Its intracellular life cycle requires host sphingolipids, which are in part acquired through the ER-Golgi localized ceramide transport protein (CERT). The Chlamydia-encoded inclusion membrane protein IncD is composed of two closely linked long hydrophobic domains with their N- and C-termini exposed to the host cytosol. IncD binds directly to the pleckstrin homology (PH) domain of CERT, likely redirecting ceramide to the inclusion. The precise regions of IncD required for this interaction have not been delineated. Using co-transfection studies together with phylogenetic studies, we demonstrate that both the IncD N- and C-terminal regions are required for binding to the CERT PH domain and define key interaction residues. Native gel electrophoresis analysis demonstrates that the transmembrane region of IncD forms SDS-resistant but dithiothreitol-sensitive homodimers, which in turn can assemble to form higher order oligomers through additional N- and C-terminal domain contacts. IncD oligomerization may facilitate high affinity binding to CERT, allowing C. trachomatis to efficiently redirect host ceramide to the inclusion.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2015

Collagen I and the fibroblast: High protein expression requires a new paradigm of post-transcriptional, feedback regulation

Scaling protein production seems like a simple perturbation of transcriptional control. However, when embryonic tendon fibroblasts have to produce 450% procollagen and secrete it from the cell 4 times faster than the average protein, this taxes the cellular machinery and requires a fresh look at how the pathway is controlled. Ascorbate, a reducing agent, can stimulate procollagen production 6-fold. Procollagen mRNA levels goes up 6-fold but requires 3 days for the cell to accomplish this task. Secretion rates, the last cellular step in the process, also goes up 6-fold but this occurs in o1 h. What regulatory scheme is consistent with these properties? Scope of this review: This review focuses on fibroblasts that make high levels of procollagen (type I) and how they regulate the collagen pathway. Data from many different labs are relevant to this problem but it is hard to see the bigger picture from a large number of small studies. This review aims to consolidate this data into a coherent model and this requires solutions to some controversies and postulating potential mechanisms where the details are still missing. Major conclusions: In high collagen producing cells, the pathway is controlled by post-transcriptional regulation. This requires feedback control between secretion and translation rates that is based on the helical structure of the procollagen molecule and additional tissue-specific modifications. General significance: Transcriptional control does not scale well to high protein production with rapid regulation. New paradigms lead to better understanding of collagen diseases and tendon morphogenesis.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2016

A synthesis of environmental and recreational mitigation requirements at hydropower projects in the United States

Environmental mitigation plays an important role in the environmentally sustainable development of hydropower resources. However, comprehensive data on mitigation required by the Federal Energy Regulatory Commission (FERC) at United States (US) hydropower projects is lacking. Therefore, our objective was to create a comprehensive database of mitigation required at non-federal hydropower projects and provide a synthesis of available mitigation data. Mitigation data was collated for over 300 plants licensed or relicensed from 1998 through 2013. We observed that the majority of FERC mitigation requirements deal with either hydrologic flows or recreation and that hydropower plants in the Pacific Northwest had the highest number of requirements. Our data indicate opportunities exist to further explore hydropower mitigation in the areas of environmental flows, fish passage, and water quality. Lastly, connecting these data with ecological outcomes, actual flow data, and larger landscape level information will be necessary to evaluate the effectiveness of mitigation and ultimately inform regulators, managers, and planners.

13 HYDRO ENERGY↗

DOE OSTI2012

Prone Accelerated Partial Breast Irradiation After Breast-Conserving Surgery: Compliance to the Dosimetry Requirements of RTOG-0413

Purpose: The dosimetric results from our institution's trials of prone accelerated partial breast irradiation are compared with the dosimetric requirements of RTOG-0413. Methods and Materials: Trial 1 and Trial 2 are 2 consecutive trials of prone-accelerated partial breast irradiation. Eligible for both trials were stage I breast cancer patients with negative margins after breast-conserving surgery. The planning target tumor volume (PTV) was created by extending the surgical cavity 2.0 cm for Trial 1 and 1.5 cm for Trial 2, respectively. Contralateral breast, heart, lungs, and thyroid were contoured. Thirty Gray was delivered in five daily fractions of 6 Gy by a three-dimensional conformal radiation therapy technique in Trial 1 and were by image-guided radiation therapy/intensity-modulated radiation therapy in Trial 2. Dosimetric results from the trials are reported and compared with RTOG 0413 requirements. Results: One hundred forty-six consecutive plans were analyzed: 67 left and 79 right breast cancers. The plans from the trials complied with the required >90% of prescribed dose covering 90% of PTV{sub E}VAL (=generated from the PTV by cropping 0.5 cm from the skin edge and excluding the chest wall): V90% was 98.1 {+-} 3.0% (with V100% and V95%, 89.4 {+-} 12.8%, 96.4 {+-} 5.1%, respectively). No significant difference between laterality was found (Student's t test). The dose constraints criteria of the RTOG-0413 protocol for ipsilateral and contralateral lung (V30 <15% and Dmax <3%), heart (V5 <40%), and thyroid (Dmax <3%) were satisfied because the plans showed an average V5% of 0.6% (range, 0-13.4) for heart, an average V30% of 0.6% (range, 0-9.1%) for ipsilateral lung, and <2% maximum dose to the thyroid. However, our partial breast irradiation plans demonstrated a higher dose to contralateral breast than that defined by RTOG constraints, with a median value of maximum doses of 4.1% (1.2 Gy), possibly as a result of contouring differences. Conclusions: Our technique for prone accelerated partial breast irradiation generally satisfied RTOG-0413 requirements.

62 RADIOLOGY AND NUCLEAR MEDICINE↗