bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas‐Phase Alkali‐Metal Cation Affinities of Stabilized Enolates
Authors: Eisele Niklas F. , Rahrt Rene , Giachanou Lamprini , Shikho Fadi , Koszinowski Konrad 
Published: September 2023

AbstractThe chemistry of alkali‐metal enolates is dominated by ion pairing. To improve our understanding of the intrinsic interactions between the alkali‐metal cations and the enolate anions, we have applied Cooks’ kinetic method to determine relative M+ (M=Li, Na, K) affinities of the stabilized enolates derived from acetylacetone, ethyl acetoacetate, diethyl malonate, ethyl cyanoacetate, 2‐cyanoacetamide, and methyl malonate monoamide in the gas phase. Quantum chemical calculations support the experimental results and moreover afford insight into the structures of the alkali‐metal enolate complexes. The affinities decrease with increasing size of the alkali‐metal cations, reflecting weaker electrostatic interactions and lower charge densities of the free M+ ions. For the different enolates, a comparison of their coordinating abilities is complicated by the fact that some of the free anions undergo conformational changes resulting in stabilizing intramolecular interactions. If these complicating effects are disregarded, the M+ affinities correlate with the electron density of the chelating functionalities, that is, the carbonyl and/or the nitrile groups of the enolates. A comparison with the known association constants of the corresponding alkali‐metal enolates in solution points to the importance of solvation effects for these systems.
Prediction of Strong Solvatochromism in a Molecular Photocatalyst**
Authors: Putra Miftahussurur Hamidi , Bagemihl Benedikt , Rau Sven , Groß Axel 
Published: September 2023

AbstractBased on quantum chemical calculations, we predict strong solvatochromism in a light‐driven molecular photocatalyst for hydrogen generation, that is we show that the electronic and optical properties of the photocatalyst strongly depend on the solvent it is dissolved in. Our calculations in particular indicate a solvent‐dependent relocation of the highest occupied molecular orbital (HOMO). Ground‐state density functional theory and linear response time‐dependent density functional theory calculations were applied in order to investigate the influence of implicit solvents on the structural, electronic and optical properties of a molecular photocatalyst. Only at high dielectric constants of the solvent, is the HOMO located at the metal center of the photosensitizer, whereas at low dielectric constants the HOMO is centered at the metal atom of the catalytically active complex. We elucidate the electronic origins of this strong solvatochromic effect and sketch the consequences of these insights for the use of photocatalysts in different environments.
Separation of CTCs from WBCs using DEP‐assisted inertial manipulation: A numerical study
Authors: Uddin Mohammed Raihan , Sarowar Md Tanbir , Chen Xiaolin 
Published: September 2023

AbstractIsolation and detection of circulating tumor cells (CTCs) hold significant importance for the early diagnosis of cancer and the assessment of therapeutic strategies. However, the scarcity of CTCs among peripheral blood cells presents a major challenge to their detection. Additionally, a similar size range between CTCs and white blood cells (WBCs) makes conventional microfluidic platforms inadequate for the isolation of CTCs. To overcome these challenges, in this study, a novel inertial‐dielectrophoretic microfluidic channel for size‐independent, single‐stage separation of CTCs from WBCs has been presented. The proposed device utilizes a spiral microchannel embedded with interdigitated electrodes. A numerical model is developed and validated to investigate the influence of various parameters related to the channel design, fluid flow, and electrode configuration. It was found that optimal separation of CTCs could be obtained at a relatively low voltage, termed the critical voltage. Furthermore, at the critical voltage of 7.5 V, the hybrid microchannel is demonstrated to be capable of separating CTCs from different WBC subtypes including granulocytes, monocytes, T‐, and B‐lymphocytes. The unique capabilities of the hybrid spiral microchannel allow for this size‐independent isolation of CTCs from a mixture of WBCs. Overall, the proposed technique can be readily utilized for continuous and high‐throughput separation of cancer cells.
ScRNA‐seq revealed disruption in CD8+ NKG2A+ natural killer T cells in patients after liver transplantation and immunosuppressive therapy
Authors: Fang Yuan , Bian CongWen , Li ZhiTao , Jin Li , Chen ChuHong , Miao YingLei , Huang HanFei , Zeng Zhong 
Published: September 2023

AbstractBackgroundLiver transplantation (LT) offers a good survival chance for both the patient in short or long term, but still faces many challenges in the treatment of LT, such as the side effects associated with long‐term immunosuppression, which is one of the side effects that occurs in most patients. However, the dynamics of the cellular immune system composition over time during immune tolerance to LT after immunosuppressive therapy are not known.MethodsUsing single‐cell transcriptome sequencing, we analyzed five peripheral blood samples (one normal individual and four patients who underwent LT and received immunosuppressive therapy for 2 months, 1 year, 3 years, and 7 years, respectively) for immune cell composition and gene expression.ResultsA total of 17,462 peripheral blood mononuclear cells were acquired from a normal individual without LT and patients who underwent LT and received immunosuppressive therapy for 2 months, 1 year, 3 years, and 7 years, respectively. A total of 24 cell clusters were obtained and categorized into four different cell types based on gene expression characteristics as follows: eight clusters of T cells, two clusters of B cells, two clusters of neutrophils, two clusters of monocytes, natural killer cells, and natural killer T (NKT) cells (n = 4), and six other cell clusters. Cell subset analysis, pseudotime analysis, and intercellular communication analysis revealed that the CD8+ NKT cells specifically expressed NKG2A (KLRC1, CD159A), which may be an important cell group for CD8+ NKG2A+ NKT cells in LT, thereby highlighting the heterogeneity and functional diversity in patients who undergo LT.ConclusionsWe comprehensively analyzed single‐cell RNA sequencing data from a normal individual and patients who underwent LT and elucidated the mechanism underlying the development of immune tolerance in LT. CD8+ NKT cells specifically expressing KLRC1 play a crucial role in LT, and dynamic monitoring of these cells may provide novel avenues for the diagnosis and treatment of LT‐related immune rejection.
Digital Engineering Enablers for Systems Engineering in Early‐Stage Research and Development
Authors: Granados Arno , Tseng Celia 
Published: September 2023

ABSTRACTRobust systems engineering is perceived as an unnecessary cost and schedule burden when the goal is proof of concept in an early‐stage project (TRL 1‐5). In reality the majority of industry, as opposed to academic, early‐stage research and development (ESR&D) efforts are generally not “pure research”, but instead focus on technology development for the purpose of technology transition to applied development and technology insertion into new or existing products. To overcome the barriers, an early and active end‐user focused system engineering approach is needed to build the use cases to support the transition from fundamental research to applied development. Digital engineering (DE) enablers can lower the transition investment cost through the use of agile methodologies, reference architectures, and model‐based design and manufacturing capabilities. End‐to‐end digital continuity from ESR&D to manufacturing and sustainment facilitates early discoveries of transition risks, which enable informed decision‐making to mitigate pitfalls leading to the “valley of death.”This article leverages efforts associated with Industry 4.0, digital engineering transformation and INCOSE working group efforts to illustrate how a systems engineering approach based on DE concepts facilitates rapid instantiation of key systems engineering process and elements in ESR&D projects. This approach is both enabling to foundational ESR&D efforts, and transformational in building a bridge across the valley of death to foster success in technology transition to product. An agnostic tool, standards‐based framework is presented, and specific tools are used to illustrate ESR&D transformation.
The Systems Engineering Process Working Group: A Status Report
Authors: Wray Richard B. 
Published: September 2023

AbstractThe national body of the National Council on Systems Engineering (NCOSE) has chartered the Systems Engineering Process Working Group (SEP WG) to refine and describe systems engineering processes). The challenges and questions have been identified, goals and results needed have been defined, and a development approach selected. Active since April 1992, the SEP WG has made progress in resolving some key issues and preparing a description which is useful to the practicing systems engineer. This paper describes the background, action plan, approach and current status of the SEP WG.
STATE OF THE PRACTICE‐COMMERCIAL SYSTEMS ENGINEERING
Authors: Iliff Randall C. 
Published: September 2023

AbstractThis paper was prepared to document the current state of Systems Engineering practice in the Commercial Sector. The paper covers Commercial Sector acceptance / application of Systems Engineering and related National Council on Systems Engineering (NCOSE) activities to date. Underlying factors motivating recent changes to the role of Systems Engineering in the Commercial Sector are also identified and discussed.
ADAPTIVE SYSTEMS ENGINEERING: A CONCEPTUAL MODEL
Authors: Shenhar Aaron J. , Bonen Zeev 
Published: September 2023

AbstractThe conceptual and theoretical basis of systems engineering and project management are still in their early days. For example, almost all literature written in recent years in these areas tend to assume that all projects are fundamentally similar and their management consists of a universal set of functions and activities. Systems engineering books usually describe a system's lifecycle (phases) and typical systems engineering process activities along these phases. In practice however, there are salient differences among systems according to size, industry, customer type, contractor's organization, level of technology and other parameters.Based on an exploratory, on‐going field study we suggest in this paper a conceptual, two dimensional framework for the classification of projects and systems and show how this framework can be used to distinguish among systems engineering styles and practices for various types of engineering projects. Projects are classified according to their level of technological uncertainty at the moment of project initiation and their system scope which is their location on a hierarchy of systems and subsystems. The technological uncertainty dimension is divided into: low‐tech, medium‐tech, high‐tech, and, super high‐tech projects. System scope is divided into: assembly, system and array projects. Considerable differences were found among systems engineering methods along each one of the model's axes. Differences were also observed for a simultaneous change in both dimensions.
REAL TIME SYSTEMS/SOFTWARE METHODOLOGIES FOR LARGE AEROSPACE SYSTEMS
Authors: Patel Bhadra K. , Tamanaha Doris Y. , Rudzik Laurel A. 
Published: September 2023

AbstractThis paper presents an overview of the real time system/software methodology approach being deployed within Hughes Aircraft Company. The Hatley‐Pirbhai Process for System Development (PSD) was chosen as the training standard for all systems and software engineers in a common engineering method to increase productivity, quality of design, and communications between various engineering disciplines. The approach that Hughes has taken is to adopt a well defined and proven methodology available from industry and to customize it to include specific extensions applicable to the types of systems developed by Hughes Aircraft product organizations. Two such extensions, information modeling and requirements traceability tooling, are discussed in this paper. In conclusion, the paper will discuss the lessons learned for using the integrated system development methodology and follow‐on activities that are being worked on today.
Functional Analysis Vs. Object Oriented Analysis, A View from the Trenches
Authors: Brown Phillip J. , Cady Kim A. 
Published: September 2023

AbstractSystem engineering has long used a structured analysis approach widely known as functional analysis. Recent experience in software development has resulted in a growing enthusiasm for object oriented analysis, a system analysis technique focused on the objects within the system, and the objects external to the system, with which the system interacts. While many analysts view these two perspectives as an either/or choice, this paper contends that these methods are complementary, providing system and software engineers a cross‐checking process for establishing a stable set of well defined requirements. Furthermore, exploitation of the unique strengths of each approach yields a diminishing volume of work as the software sub‐elements are refined for use in a production system.
ACCELERATING SYSTEM INTEGRATION
Authors: Jenkins Roger , VanNostrand Erik 
Published: September 2023

AbstractThis paper presents a case study on the combined contributions of system simulation, technical interchange, and innovative methods of system analysis toward the acceleration of system integration. The combination of these three efforts cut cost and increased productivity so that aggressive program schedules could be maintained. Capitalizing on unique opportunities, simulations and innovative real time methods of analysis played a key role in the timely integration of a highly advanced multiprocessor system.
“Working Together”: The Boeing 777 Cabin Management System
Authors: Morrison Arthur F. 
Published: September 2023

AbstractThe new Boeing 777 Cabin Management System (CMS) is being developed by the Boeing Defense & Space Group Commercial Avionics Systems (CAS) for the Boeing Commercial Airplane Group (BCAG). CAS is performing the detailed system engineering based on BCAG provided system requirements. With both of these groups involved in the development effort, the system engineering process being employed utilizes system engineering elements from both organizations. As might be expected, combining system engineering methods from both groups necessitates the use of an integrated approach. Challenges arise from administrative as well as technical viewpoints. Many considerations have to be addressed, including the level of functional development and system architecture definition specified by each group, the use of requirement development teams and their responsibilities, the form and content of the deliverable system engineering products, and the establishment of and requirements for key system engineering milestones.This paper defines the various aspects of the system engineering approach being applied to the Boeing 777 CMS system engineering task. The steps that have been taken to integrate the two groups are explained and analyzed to provide insight into how to apply an integrated system engineering approach to a product development effort.
Automated Optimization of Systems Architectures for Performance
Authors: Oliver David W. 
Published: September 2023

AbstractThis paper provides a brief executive level description of Model Based Systems Engineering, (MBSE). It introduces the seven abstract core engineering steps that can be used to describe the engineering process and make the process tailorable. A representative set of tools is described that can span the engineering work.The MBSE process, with a tool set is described, as a means to automate the search of the application solution space for feasible or near optimal systems solutions. The approach applies to distributed and real‐time systems. A by‐product of the approach is an automated ability to reuse systems specifications and systems designs.A simple example is provided to show how the optimization works. It shows how modeling and automation augment inspired engineering but do not substitute for it. Substantial work is needed in information standards for systems, tools integration, and search procedures.
Educating System Engineers: What Industry Needs and Expects Universities or Training Programs to Teach
Authors: Might Robert J. , Foster Robert A. 
Published: September 2023

AbstractDo universities provide industry with System Engineers (SEs) that industry expects and wants? Are company sponsored training programs for System Engineers a worthwhile investment? Unlike traditional engineering disciplines, there is no prescribed educational program for Systems Engineering that meets the majority of industry's needs. Consequently, there appears to be no way for an organization to hire graduates who will, with certainty, be qualified to perform the majority of systems engineering functions within that organization. How much of this is due to the lack of standardization within industry, and how much is due to the lack of a standardized academic curriculum? This paper presents results of an empirical study aimed at identifying answers to these and other questions that are extremely important to the development of a close, effective partnership between industry (the customer) and educational/training programs (the producers).
THE NASA/USRA UNIVERSITY ADVANCED DESIGN PROGRAM: A SYSTEMS ENGINEERING EXPERIENCE
Authors: Johnson Vicki S. , Rumbaugh Barbara A. 
Published: September 2023

AbstractThis paper describes the NASA/USRA University Advanced Design Program (ADP) and the role it plays in providing a systems engineering experience for senior engineering students in “capstone” design courses. Experience with the program has resulted in conclusions about the factors that contribute to a positive experience in the course, with parallels drawn to the “real world.” The paper also presents on‐going ADP activities designed to expand the impact of the program to a wider community.
Database Generated Software Requirements Specification
Authors: Crocker Don 
Published: September 2023

AbstractThe goal of software requirements management at Grumman is to provide Systems Engineering's internal and external customers with the right information to produce and evaluate a computer program that meets the system's needs. A valuable approach to requirements management is to model one or more aspects of a system and communicate and control the system and software requirements via a database of the model elements.Engineering models can range from abstract models such as a series of partial differential equations for the solution of harmonic vibrations to isomorphic models such as a data flow diagrams or perspective drawings. The modeling method chosen uses a graphical notation and an Entity‐Relationship‐Attribute (ERA) database to create four isomorphic models to define a system and is currently implemented using RDD‐100® from Ascent Logic Corporation.The models used to specify the system are:1) Design Knowledge Capture (DKC) model‐an ERA model of the requirements flowdown from the perceived need to the requirements specification. 2) Behavior model – built using entities that represent functions and items, along with temporal notations of the functional flow. 3) Physical model –sometimes called the system architecture, includes the hierarchical structure of the components that build the system, the interfaces between the components, and the physical links that comprise the interfaces. 4) Resource model‐allows the engineer to evaluate the amount of resources needed when specified behavior is exhibited by a system architecture and to determine the behavior of the system when resources are depleted.The customization of the RDD language and the augmentation of RDD with other tools to add the required capability is described. The elements of the model are mapped from the RDD database to the an expansive interpretation of the Data Item Description for a Software Requirements Specification (DI‐MCCR‐80025A). The interpretation is based on interchanges between the requirements provider and the requirements implementor.The paper describes the aspects of systems specified using the database of models method. The method is heavily driven by the need to meet the MIL‐STD 2167A requirements for a Software Requirements Specification. However; the main value of this paper may be in the identification of the information produced while engineering the system that is not in the Systems Requirements Specification (SRS).
IN DEFENSE OF THE TRADITIONAL SYSTEM REQUIREMENTS ANALYSIS PROCESS
Authors: Grady Jeffrey O. 
Published: September 2023

ABSTRACTSome new requirements tools and techniques carry with them the suggestion that the traditional system requirements analysis (SRA) process is somehow deficient and passé. This paper re‐visits that process, expands its structured decomposition techniques to include alternatives to functional flow diagramming, augments it with structured interface, environmental, and specialty engineering requirements analysis and adapts it to the Integrated Product Development (IPD) approach.In the traditional SRA approach, it was never clearly explained how it began, leaving many to conclude that there was a chicken‐and‐egg problem hiding in there somewhere. It also was never clear where it ended (decompose as required). Some have concluded that the process has neither beginning nor end, only a very expensive middle producing paper of great mass but questionable utility. The traditional process also focused principally on performance requirements. It provided an effective demand driver for only one of three kinds of constraints and had little to offer for programmatic requirements analysis.All of these shortcomings are disposed of in this paper revealing a comprehensive, flexible, and robust approach to project‐wide requirements analysis linked to recent advances like quality function deployment (QFD), IPD concepts, and the U.S. Air Force integrated planning initiative. The process is described more fully in a new book about an old process titled System Requirements Analysis (Grady 1993).
SYSTEMS ENGINEERING PERFORMANCE ANALYSIS THROUGHOUT THE SYSTEMS ACQUISITION LIFECYCLE
Authors: Atallah George C. 
Published: September 2023

AbstractToday's systems and their applications incorporate a variety of complex, physical, logical, and human elements. The interactions between these elements are often so complex that intuition alone is not sufficient for estimating the performance indices of interest. These systems, under a tremendous heavy workload, are expected to generate high throughput at a reasonable level of resources' utilization, fast response time, and maintain high level of quality (such as availability, reliability, and maintainability). These challenging technical performance specifications have imposed on the applications of interest numerous critical technical problems throughout their entire acquisition lifecycles. This paper defines, introduces and addresses a comprehensive systematic performance process to quantify and analyze these technical problems. This performance process identifies and organizes the system performance measurements; structures and addresses its major steps throughout the entire system acquisition lifecycle. Proper implementation of this performance process will ensure on time delivery of high quality and low cost systems.