Payload Structure Research Articles

Introduction of a Novel Structure for a Light Unmanned Free Balloon's Payload: A Comprehensive Hybrid Study.

Payloads for light unmanned free balloons must meet several safety requirements such as being able to protect the inner electronics in order to extract scientific data and to reduce the chance of inflicting personal injury in case of an accidental fall. This article proposes a novel payload structure, which exhibits the form of a dodecahedron. The actual form was determined by carrying out theoretical drop tests on different polyhedrons using the finite element method (FEM). From the simulations, it could be deduced that the dodecahedron was the optimal choice, since the duration of the impact was longer, while the impact force was slightly lower. The payload was produced by additive technologies; therefore, after performing tensile tests on probable materials, PLA was selected as the optimal candidate. The theoretical results about the dodecahedron's ability were validated by laboratory and real-life drop tests, where the new payload was subjected to 56% less impact force under a 78% longer collision time compared to a classic, rectangular cuboid design. Based on these tests, it was demonstrated that the new structure is safer and it is applicable.

Laboratory investigations of sub-meter resolution telescope with segmented aperture dedicated to CubeSat platform

In current CubeSat observation satellites, the main design constraint is the available space. Standards dictating the unit dimensions of the payload severely restrict the maximum aperture and focal length of the optical instrument. In this paper, the authors present the results of work to produce a novel DeploScope optical system for a CubeSat-type observation satellite with a segmented aperture of the primary mirror deployed in space. The telescope is designed for Earth observation and is expected to find its application in the military, precision agriculture or environmental disaster prevention. The work includes a detailed analysis of the segment aperture effect on image repeatability for different numbers of main mirror segments. Based on it, the optimal configuration of the optical model of the telescope with an aperture of 188.5 mm and a focal length of 1100 mm was selected. Based on this analysis, a so-called laboratory version of the telescope was built, providing the possibility of free correction of each segment of the primary mirror while maintaining a solid stable base for other components of the module. Imaging tests were carried out on the laboratory version of the instrument and the system was optimized for a version suitable for implementation in the payload structure of the microsatellite.

A Phase 1 Cohort Dose Escalation and Expansion Trial to Determine the Safety, Tolerance, Maximum Tolerated Dose, and Preliminary Antineoplastic Activity of IKS03 in Patients with Advanced B-Cell Non-Hodgkin Lymphomas (NHL)

Background: IKS03 is an antibody-drug conjugate (ADC) comprising an anti-CD19 antibody conjugated with novel ConjuALL technology to a highly potent proprietary DNA-crosslinking pyrrolobenzodiazepine (PBD) prodrug payload for the treatment of CD19-positive hematologic malignancies. Both the payload and the linker of IKS03 incorporate an innovative tumor-selective chemistry that takes advantage of the overexpression of beta glucuronidase in cancer cells compared to most normal tissues. Payload release and activation require cleavage of glucuronide moieties that are incorporated into the linker payload structure providing improvements in both efficacy and safety compared to traditional ADC formats. This “glucuronide trigger” is stable while in circulation with minimal to no systemic payload release from the ADC. Following binding and internalization of IKS03 into a CD19-positive cancer cell, beta glucuronidase can release the active PBD payload leading to cell death. Normal tissues without CD19 expression and/or with low levels of the beta glucuronidase enzyme have limited ADC uptake, are less able to process IKS03 and are differentially spared. In preclinical studies, IKS03 demonstrated significant in vivo efficacy with complete tumor regressions in CD19-positive diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), and mantle cell lymphoma (MCL) xenograft models at single doses of 0.1 to 1 mg/kg. IKS03 demonstrated greater activity than the clinical benchmark ADC loncastuximab tesirine. IKS03 is also highly effective in patient-derived xenograft models that contain some of the genetic alterations commonly found in relapsed/refractory NHL patients. Results from toxicology studies in cynomologus monkey suggest a manageable safety profile at single doses, well above those required for in vivo activity. Pharmacokinetics are favorable with a mean total ADC half-life of 8 days and undetectable levels of the active PBD payload in circulation confirming targeted delivery of the payload. Study Design and Methods: This Phase 1 multicenter, open label, non-randomized study of IKS03 will consist of two parts: dose-escalation (Part I) and dose-expansion (Part II) together enrolling approximately 140 adult patients with relapsed or refractory B-cell NHL after at least two prior lines of systemic therapy. Patients will receive repeat doses of study drug by IV infusion on Day 1 of each 21-day cycle, until disease progression, unacceptable toxicity, or another withdrawal criterion is met. Key exclusion criteria include: active central nervous system involvement with NHL; clinically significant cardiovascular, pulmonary or hepatic disease; or receipt of other CD19-directed therapy within 3 months. Part I dose escalation will enroll patients with confirmed CD19-positive, measurable or non-measurable advanced B-cell NHL. Eligible subtypes include DLBCL, MCL, FL, high-grade B-cell, and marginal zone lymphoma as per WHO 2016 classification. Patients with Burkitt's lymphoma, Waldenström macroglobulinemia, and chronic lymphocytic leukemia are excluded. In Part 1, the primary objective is establishment of the recommended Phase 2 dose (RP2D) by evaluation of safety, tolerability and the maximum tolerated dose (MTD) of IKS03. Dose escalation will follow a 3+3 design. A two cycle Dose-Limiting Toxicity (DLT) assessment period will be observed, and dose-escalation decisions will be guided by a study safety committee. Dose escalation increments will be adjusted based on occurrence of protocol-specified DLTs as well as overall tolerability. Secondary objectives include characterization of immunogenicity and pharmacokinetic (PK) profile of IKS03. Exploratory objectives include preliminary antineoplastic activity per Lugano criteria (Cheson et al, JCO 2014) and evaluation of pharmacodynamic markers. Part II will further evaluate the antineoplastic activity of IKS03 at the RP2D in expansion cohorts of patients with selected NHL subtypes and with measurable disease. Sample size will be determined for each subtype using a Simon Two-Stage design. Secondary objectives include further evaluation of safety, tolerability, immunogenicity and PK profile of IKS03 as well as confirmation of the RP2D. Clinical trial information: NCT05365659.

Payload Design for the Space Elevator Climber

It is feasible, with present-day or soon-to-be available technology, to build a 20-tonne space elevator climber with room for 10 tonnes of payload. The type of payload will require modifications to the climber design and affect the stresses in the climber and in the space elevator tether. An iterative, finite element analysis was undertaken to study these stresses and to provide a first conceptual design of a payload support structure. The example of liquid oxygen transport to orbit was chosen. Unexpected stresses due to off-center payloads, uneven compressive forces due to overhung payload mass and unequal tensions in the tether were uncovered and solutions for alleviating these stresses were incorporated into the final design. Though the design for the support of liquid oxygen tanks was specialized for that particular payload, a similar design could be used for more general cargo and might resemble that used for intermodal freight containers. Keywords: Space Elevator, Engineering, Design, Finite Element Analysis

Beyond vanilla: Improved autoencoder-based ensemble in-vehicle intrusion detection system

Modern automobiles are equipped with a large number of electronic control units (ECUs) to provide safe, driver assistance and comfortable services. The controller area network (CAN) provides near real-time data transmission between ECUs with adequate reliability for in-vehicle communication. However, the lack of security measures such as authentication and encryption makes the CAN bus vulnerable to cyberattacks, which affect the safety of passengers and the surrounding environment. Detecting attacks on the CAN bus, particularly masquerade attacks, presents significant challenges. It necessitates an intrusion detection system (IDS) that effectively utilizes both CAN ID and payload data to ensure thorough detection and protection against a wide range of attacks, all while operating within the constraints of limited computing resources. This paper introduces an ensemble IDS that combines a gated recurrent unit (GRU) network and a novel autoencoder (AE) model to identify cyberattacks on the CAN bus. AEs are expected to produce higher reconstruction errors for anomalous inputs, making them suitable for anomaly detection. However, vanilla AE models often suffer from overgeneralization, reconstructing anomalies without significant errors, resulting in many false negatives. To address this issue, this paper proposes a novel AE called Latent AE, which incorporates a shallow AE into the latent space. The Latent AE model utilizes Cramér’s statistic-based feature selection technique and a transformed CAN payload data structure to enhance its efficiency. The proposed ensemble IDS enhances attack detection capabilities by leveraging the best capabilities of independent GRU and Latent AE models, while mitigating the weaknesses associated with each individual model. The evaluation of the IDS on two public datasets, encompassing 13 different attacks, including sophisticated masquerade attacks, demonstrates its superiority over baseline models with near real-time detection latency of 25ms.

Mechanical Structure Design and Experimental Study of Gamma-ray Monitor for Small Satellite Payload

In this paper, a novel mechanical structure for a gamma-ray monitor (GRM) is designed for a small satellite payload. Its structural stiffness, strength and dynamic response are directly related to the performance of the novel GRM, which must meet the static and dynamic characteristic requirements of the structure in a harsh vibration environment. The static and dynamic simulation of the structure are carried out by finite element method (FEM), and the mechanical structure response laws of the novel GRM are analyzed and validated by vibration tests. Through comparing the frequency response simulation results with the vibration test results, the minimum safety factor of the key components of the structure is 4.07, the fundamental frequency error is within 5.04%, the acceleration response error is within 8.5%, the root mean square of total acceleration (Grms) error is within 14.2%, and the sinusoidal characteristic sweep frequency error before and after the vibration test is within 5.0%. The results show that the payload structure has large structural stiffness, high strength and reasonable frequency response characteristics, and meets the design requirements.

Abstract 5616: Tumor-targeted immune activation via a site-specific TLR7-agonist antibody-drug conjugate

Abstract Traditional antibody-drug conjugates (ADCs) selectively deliver cytotoxic payloads to tumor-associated antigen (TAA)-expressing tumor cells, thereby limiting healthy cell damage and toxicities associated with systemic administration. Analogously, a novel class of immune-stimulating antibody conjugates (ISACs) has recently emerged to achieve tumor-targeted activation of anti-tumor immune responses, avoiding dose-limiting immunotoxicities seen with the systemic immune agonist delivery. Most of the ADC or ISAC to date utilize random payload conjugation to native surface-exposed lysines or cysteines, and relatively labile linkage chemistries, leading to conjugation site and drug-to-antibody ratio (DAR) heterogeneity, and ADC/ISAC instability in systemic circulation. In particular, the presence of high-DAR species and linker instability can lead to off-tumor toxicity, thus limiting the therapeutic window. Here we describe the generation and preclinical characterization of a site-specific TLR7-agonist (TLR7a) ISAC targeting an undisclosed TAA1. To specify the conjugation site and DAR, a non-natural amino acid (nnAA), para-acetyl-L-phenylalanine (pAF) was genetically incorporated at defined sites within the anti-TAA1 antibody, providing an orthogonal chemical handle for covalent TLR7 agonist payload conjugation through a highly stable oxime bond. Using this site-specific, homogenous ISAC platform, we systematically screened different conjugate sites and TLR7 agonist payloads to obtain an optimized TAA1-TLR7a ISAC drug candidate. ISAC platform stability, homogeneity, and flexibility were critical, because conjugation site and payload structure dramatically influenced ISAC in vitro activity, PK profile and in vivo efficacy. Using in vitro co-culture assays with human immune cells and tumor cell lines, we showed that the optimized TAA1 ISAC can induce multiple anti-tumor immune mechanisms, including proinflammatory cytokine production, the myeloid cell activation markers induction and enhanced ADCC mediated tumor cell killing. The TAA1 ISAC is 100-fold more active than the free, unconjugated TLR7 agonist, and all activity is conditional on the presence of TAA1-expressing tumor cells. Finally, we demonstrated in vivo efficacy in both xenograft and syngeneic tumor models. In a syngeneic MC38-tumor model expressing human TAA1, ISAC treatment led to complete tumor regression and formation of immunologic memory. These results provide a strong rationale for site-specific TLR7 agonist ISAC as a next generation platform for tumor-targeted, innate immune agonist immunotherapy. Citation Format: Mingchao Kang, Sung-Ju Moon, Ji Young Kim, Andy Beck, Molly Allen, Jay Nelson, Keith Tatsukawa, Hon Tran, Manoj Pal, Michael Gray, Nick Knudsen, Lillian Skidmore, David Mills, Yingchun Lu, Ying Buechler, Sukumar Sakamuri, Shawn Zhang, Feng Tian. Tumor-targeted immune activation via a site-specific TLR7-agonist antibody-drug conjugate [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5616.

Analysis and Design Multiple Layer Adaptive Kalman Filter Applied to Electro-Optical Infrared Payload Vision System

This study designs a trigger to determine the number of layers of a multi-layer adaptive Kalman filter and applies it to optoelectronic infrared payload system vision. This feature reduces the number of mechanically stabilized motors, equipment weight, CPU resources, and power for an electro-optical infrared payload system. The goal is to reduce the traditional use of multiple gyroscopes to perform calibration measurements on different gimbal frames by this design. In this study, mathematical modeling was carried out for the three-axis, three-frame camera stabilizer system, and the system foundation without motor and gimbal frame was established to achieve aperture-type camera mode. The exposure of the drone’s payload structure outside the aircraft can be reduced. This study provides the adaptive Kalman filter with the offset parameters of the camera image Minimum Output Sum of Squared Error and the three-axis degrees of freedom vector and angle data on the gyroscope. By using the image processing unit, the offset was corrected at each frame per second. The experimental results show that under the same hardware, failure limit and camera field of view constraints. The processing time by this method was compared to the traditional frame correction and full image stabilization methods. The results show that the proposed method can shorten 6 microseconds under the traditional method and can be used to provide lower power consumption, lower image delay, and a larger viewing angle range.

Research on the Transmissibility of Wire Rope Insulators as Damping Equipment on the RX 200 Rocket Payload

Wire rope insulator or steel wire rope insulator has applications for vibration isolation in equipment and structures in many industrial machinery. Steel wire rope insulators can also be used as suitable equipment to dampen vibrations in rocket loads. The disturbance acceleration as the excitation caused by the combustion process on the rocket can cause a vibration with a large amplitude which results in damage to the rocket's payload structure and the electronic equipment on the rocket's payload cannot work as desired. Based on the experience of electronic equipment, it will be damaged if the disturbance acceleration of 3 g acting on the rocket is not reduced, for this reason a vibration damping device is designed, the apparatus consists of several stainless steel wire ropes tied between two parallel binders arranged in such a way as to provides a damping effect on the rocket's payload. A wire rope insulator consists of several stainless steel wire ropes tied between two parallel straps. One application of this type of wire rope insulator is to isolate the vibrations that occur in the rocket, so that it does not interfere with the performance of the electronic equipment on the rocket's payload. Electronic equipment is used to determine the position of the rocket and its stability. In this study, the wire rope material used is stainless steel with s yield = 350 e+6 N / m2 with a diameter of d = 3 mm. The research objective of the vibratory damper of wire rope insulators was to determine the magnitude of the transmissibility of the ruffler during and after resonance. Transmissibility (TR) is the ratio of the force transmitted to the disturbing or excitation force. The results of the research on a damper with a disturbance acceleration of 3 g at resonance, obtained the transmissibility value (TR) = 2.54, the spring stiffness k = 200537.3 N/m and the damping coefficient c = 331.5 N/m/sec, then after conditions obtained transmissibility (TR) <1 This shows that the damper with steel wire isolator is good enough to dampen vibrations in the RX 200 rocket payload.

Continuous fields: Enhanced in-vehicle anomaly detection using machine learning models

The attack surface of a modern vehicle increases with its connectivity. A strategy to prevent attacks or at least to identify such attacks and to mitigate their effects is therefore imperative. The detection of indications for intrusive behavior in an in-vehicle network is an important aspect of a holistic security concept. The structure of the payload of in-vehicle messages with respect to the encoded sensor values is in general confidential. Therefore, most researchers consider the structure of the in-vehicle messages to be bit- or byte-fields. However, this may hide anomalies which are characterized by correlations between sensor values transferred by the in-vehicle messages.In this work, we evaluate the influence of accuracy of the model of the payload structure with respect to the actual sensor values on the results of different intrusion detection methods. In particular, we analyze if an improved alignment is helpful to detect anomalies introduced by stealthy intrusions.In order to cover conceptually different modeling and reasoning techniques, we adapted a deep learning approach as well as a characteristic functions based intrusion detection approach to utilize such message streams. An important aspect is that the explainability of the results is better compared to deep learning systems.We further developed a set of test vectors based on log files of a vehicle enriched by different intrusions. In particular, we included simulations of stealthy intrusions which mask certain sensor values within the respective messages. The effectiveness of the developed methods is demonstrated by various experiments.

Hydrophilic Sequence-Defined Cross-Linkers for Antibody-Drug Conjugates.

Antibody-drug conjugates (ADCs) are an established modality for the tissue-specific delivery of chemotherapeutics. However, due to the hydrophobic nature of many cytotoxic payloads, challenges remain in developing chemically stable ADCs with high drug loading. In previous studies, payload structure, unique stimuli-responsive chemistries, and PEGylated cross-linkers have been used to decrease ADC hydrophobicity. In this work, we investigate the effect of a new parameter, cross-linker sequence. A support-free synthesis of PEGylated, sequence-defined cross-linkers was developed and applied to the synthesis of three constitutionally isomeric ADCs containing PEG side chains and a monomethyl auristatin E payload. Placement of PEG side chains distally from the payload was found to yield an ADC with altered hydrophilicity, antigen binding, and in vitro potency. This work establishes a versatile method for synthesizing multifunctional cross-linkers and identifies cross-linker sequence as a new handle for modulating the performance of ADCs.

Opto-Mechanical Structure Design and Natural Frequency Analysis of Payload for Remote Sensing Satellite

This paper presents natural frequency and stress of opto-mechanical structure. In this study, an opto-mechanical structure was investigated.The opto-mechanical structure includes lens assembly and detector head assembly (DHA). The opto-mechanical structure requires high stability and position accuracy. In this design and analysis study, wide ranges of the opto-mechanical structural analysis have been performed including: Natural frequency analysis and dynamic analysis. Opto-mechanical design includes material selection and mechanical design. Payload structure design will be based on stiffness. Hence, Natural frequency is major design criteria for opto-mechanical design of payload structure. At higher vibration during launching time, resonance will be created and parts will be misaligned or may be damaged. Objective of this work is to reach maximum natural frequency with minimum stress on opto-mechanical structure.

Deuterated phytantriol – A versatile compound for probing material distribution in liquid crystalline lipid phases using neutron scattering

Phytantriol is an interfacially-active lipid that is chemically robust, non-digestible and forms particles with internal bicontinuous cubic phase structures (cubosomes) when dispersed with non-ionic surfactants at ambient and physiological temperatures. The liquid crystalline internal structure of phytantriol-based cubosomes can be changed to alter the interfacial contact area/topology with the aqueous dispersant to trigger bioactive payload release or to alter the local membrane curvature around bound or embedded proteins. To enable the study of payload distribution, structure and transformation kinetics within phytantriol particles by neutron scattering techniques it is desirable to have access to a deuterated version of this molecule but to date a synthetic route has not been available. The first successful synthesis of phytantriol-d39 is presented here alongside a preliminary physical characterisation of related particle structures when phytantriol-d39 is dispersed using two non-ionic surfactants, Tween® 80 and Pluronic® F127. Synchrotron small angle X-ray scattering (SAXS) was used to confirm that phytantriol-d39-based nanoparticles in D2O form similar liquid crystalline structures to those of their natural isotopic abundance (phytantriol/H2O) counterparts as a function of temperature. Finally, small angle neutron scattering (SANS) with solvent contrast to match out the phytantriol-d39 structuring was used to show that the spatial correlations between the Tween® and Pluronic® non-ionic surfactant molecules are different within dispersed phytantriol-d39 particles with different liquid crystalline structures in D2O. The surfactant molecules in phytantriol-d39/Tween® 80 particles with Im3m cubic structures were found to follow a self-avoiding walk, whereas in phytantriol-d39/Pluronic® F127 particles with Pn3m cubic structures they were found to follow a more rod-like packing arrangement.

NARMAX Self-Tuning Controller for Line-of-Sight-Based Waypoint Tracking for an Autonomous Underwater Vehicle

In this brief, a constrained self-tuning controller (CSTC) is developed for the heading and diving motions of an autonomous underwater vehicle (AUV) considering the parameter variation and practical realization of the algorithm. Parameters in the AUV dynamics may vary due to change in payload or physical structure. A Nonlinear Auto-Regressive Moving Average eXogenous (NARMAX) model is designed using the significant regressors to identify the AUV heading and diving dynamics, respectively. The parameters of the NARMAX model are updated using a recursive extended least square algorithm at each time instant. Furthermore, using the identified model, a CSTC law is designed to track desired waypoints using line of sight guidance law. The controller gains are updated at each instant satisfying the actuator constraint and computational efficiency is studied in view of achieving the practical implementation of the developed algorithm. The efficacy of the developed NARMAX-based CSTC algorithm to track a given reference is verified in an experimental environment with payload variation and external disturbance. From the obtained results, it is concluded that the developed control algorithm is effective for an AUV to track desired waypoints or heading/diving reference.

Assessment of the influence of the RaD-X balloon payload on the onboard radiation detectors

The NASA Radiation Dosimetry Experiment (RaD-X) stratospheric balloon flight mission, launched on 25 September 2015, provided dosimetric measurements above the Pfotzer maximum. The goal of taking these measurements is to improve aviation radiation models by providing a characterization of cosmic ray primaries, which are the source of radiation exposure at aviation altitudes. The RaD-X science payload consists of four instruments. The main science instrument is a tissue-equivalent proportional counter (TEPC). The other instruments consisted of three solid state silicon dosimeters: Liulin, Teledyne total ionizing dose (TID) and RaySure detectors. The instruments were housed in an aluminum structure protected by a foam cover. The structure partially shielded the detectors from cosmic rays but also created secondary particles, modifying the ambient radiation environment observed by the instruments. Therefore, it is necessary to account for the influence of the payload structure on the measured doses. In this paper, we present the results of modeling the effect of the balloon payload on the radiation detector measurements using a Geant-4 (GEometry ANd Tracking) application. Payload structure correction factors derived for the TEPC, Liulin, and TID instruments are provided as a function of altitude. Overall, the payload corrections are no more than a 7% effect on the radiation environment measurements.

2015 WSGC Elijah High-Altitude Balloon Payload Project Final Report

The purpose of this report is to discuss the research, development, and findings of several experiments performed on a high-altitude balloon payload platform. The team decided on the following five experiments to be performed during the flight: Oxygen Generation, Internal Heating, Speed of Sound Properties, Ozone Levels, and a new payload structure concept. The entire team was required to research and develop new skills to effectively design our experiments, including: Arduino programming, 3-D modeling/printing, soldering, launch equipment handling, and construction techniques. While the launch was successful, we did fall short of our overall goal in terms of data acquisition. The internship proved to be a rewarding introductory experience to real-world engineering. The project help us learn how to implement the entirety of the engineering process, using each person’s strengths to achieve an objective.

Random Vibration Analysis of Rivets on Payload Structure

A payload structure is joined by rivets, which are potential weakness in random vibrations and thus require safety examination. Based on the general finite element software ANSYS®, a 3D whole-local finite element model of payload structure was established. The strength evaluation method is determined for rivets through a determinate transient dynamics analysis and related experiment under half sine impulse load. A Power Spectral Density (PSD) analysis is carried out and the rivets under random vibration environment were analyzed. The results of the random vibration analysis show that the design scheme of rivets is feasible.

6.5.1 I5: A Model‐Based Framework for Architecting System‐of‐Systems Interoperability, Interconnectivity, Interfacing, Integration, and Interaction

AbstractWe present I5 — Interoperability, Interconnectivity, Interfacing, Integration, and Interaction — a Model‐Based Framework for Architecting Systems‐of‐Systems. Interoperability programs deliver end‐to‐end cooperation and collaboration capabilities and services among organizations, users, systems, and infrastructures, on top of a set of existing systems. Each system has its own programmatic and technical constraints and issues. System‐level stakeholders usually prefer core functionality over integration, and expect the interconnectivity infrastructure to be transparent and simple, regardless of its actual cost, complexity, or criticality. Hence, coordinating and aligning the multiple system and team efforts in order to reach a synergetic effect is a challenge that many integration professionals in the cyber, energy, manufacturing, and traffic domains are familiar with. Traditional system‐centered design methods fail to capture interconnectivity and collaboration aspects and issues, and they are of little interest to the individual systems' stakeholders. The framework we propose is based on Object–Process Methodology, an emerging ISO standard (ISO 19450) for modeling and design of complex, dynamic, and multidisciplinary systems. Our framework facilitates a smooth transition from a set of disparate system‐centered views to a consolidated, integrated model, which accounts for integration aspects, interface and payload structure and behavior, interconnectivity processes and services, and eventually emergent interoperability capabilities.

Abstraction, Federation, and Scalability

I've often mused about the properties of structures that make them scalable. Regularity is often an element, as in geodesic domes. Abstraction is another contributor. An example of this is the layered, hierarchical, and federated structure of the Internet. Sequences of bits (physical transmission) are organized into frames (link structure) that are organized into packets with header and payload structure. TCP organizes sequences of packets into “connections” that deliver abstract sequences of payload bytes (“octets”) and are organized into higher level abstractions. At each “level” of abstraction, the details become less visible, and emergent structure becomes apparent. Groups of computers (for example, routers) form Autonomous Systems (networks) that share a common property (an “internal gateway protocol” such as IS-IS and an “external gateway protocol” such as BGP4). Encapsulation hides the lowerlayer structure in the payload of a “higher”-layer structure.

Advancements in hybrid dynamic models combining experimental and finite element substructures

This paper presents very practical enhancements to the transmission simulator method (TSM); also known as the Modal Constraints for Fixtures and Subsystems (MCFS). The enhancements allow this method to be implemented directly in finite element software, instead of having to extract the reduced finite element model from its software and implement the substructure coupling in another code. The transmission simulator method is useful for coupling substructures where one substructure is derived experimentally and the other is generated from a finite element model. This approach uses a flexible fixture in the experimental substructure to improve the modal basis of the substructure; thus, providing a higher quality substructure. The flexible fixture substructure needs to be removed (decoupled) from the experimental substructure to obtain the true system characteristics. A modified method for this removal and coupling of the experimental and analytical substructures is provided. An additional improvement guarantees that the experimental substructure matrices are positive definite, a requirement for many finite element codes. Guidelines for designing robust transmission simulator hardware are provided. The concepts are applied to two sample cases. The first case consists of a cylinder connected by eight bolts to a plate with a beam. The second example is an outer shell structure that is connected through a bolted flange to a complex internal payload structure.