The applicability of frame imaging from a spinning spacecraft. Volume 1: Summary report

A detailed study was made of frame-type imaging systems for use on board a spin stabilized spacecraft for outer planets applications. All types of frame imagers capable of performing this mission were considered, regardless of the current state of the art. Detailed sensor models of these systems were developed at the component level and used in the subsequent analyses. An overall assessment was then made of the various systems based upon results of a worst-case performance analysis, foreseeable technology problems, and the relative reliability and radiation tolerance of the systems. Special attention was directed at restraints imposed by image motion and the limited data transmission and storage capability of the spacecraft. Based upon this overall assessment, the most promising systems were selected and then examined in detail for a specified Jupiter orbiter mission. The relative merits of each selected system were then analyzed, and the system design characteristics were demonstrated using preliminary configurations, block diagrams, and tables of estimated weights, volumes and power consumption

Integrated component-based computer design modeling system : the implications of the representation of control parameters on the design process

The design process is dependent on a clear order of integrating and managing all of the control parameters that impact on a building\u27s design. All component elements of a building must be defined by their: Physical and functional relations; Quantitative and calculable properties; Component and/or system functions. This requires a means of representation to depict a model of a building that can be viewed and interpreted by a variety of interested parties. These parties need different types of representation to address their individual control parameters, as each component instance has specific implications on all of the control parameters. Representations are prepared for periodic design review either manually through hand-drawn graphics and handcrafted models; or with the aid of computer aided design programs. Computer programs can profoundly increase the speed and accuracy of the process\u27, as well as provide a level of integration, graphic representation and simulation, untenable through a manual process. By maintaining a single control model in an Integrated Component-based Computer Design Modeling System (ICCDMS), interested parties could access the design model at any point during the process. Each party could either: 1. Analyze individual components, or constraints of the model, for interferences against parameters within that party\u27s control; or 2. Explore design alternatives to modify the model, and verify the integration of the components or functions, within the design model, as allowable in relation to other control parameters

A MIDDLE-WARE LEVEL CLIENT CACHE FOR A HIGH PERFORMANCE COMPUTING I/O SIMULATOR

This thesis describes the design and run time analysis of the system level middle-ware cache for Hecios. Hecios is a high performance cluster I/O simulator. With Hecios, we provide a simulation environment that accurately captures the performance characteristics of all the components in a clusterwide parallel file system. Hecios was specifically modeled after PVFS2. It was designed to be extensible and to easily allow for various component modules to be easily replaced by those that model other system types. Built around the OMNeT++ simulation package, Hecios\u27 inner-cluster communication module is easily adaptable to any TCP/IP based protocol and all standard network interface cards, switches, hubs, and routers. We will examine the system cache component and describe a methodology for implementing other coherence and replacement techniques within Hecios. Similar to other cache simulation tools, we allow the size of the system cache to be varied independently of the replacement policy and caching technique used

Modified Level Restorers Using Current Sink and Current Source Inverter Structures for BBL-PT Full Adder

Full adder is an essential component for the design and development of all types of processors like digital signal processors (DSP), microprocessors etc. In most of these systems adder lies in the critical path that affects the overall speed of the system. So enhancing the performance of the 1-bit full adder cell is a significant goal. In this paper, we proposed two modified level restorers using current sink and current source inverter structures for branch-based logic and pass-transistor (BBL-PT) full adder [1]. In BBL-PT full adder, there lies a drawback i.e. voltage step existence that could be eliminated in the proposed logics by using the current sink inverter and current source inverter structures. The proposed full adders are compared with the two standard and well-known logic styles, i.e. conventional static CMOS logic and Complementary Pass transistor Logic (CPL), demonstrated the good delay performance. The implementation of 8-bit ripple carry adder based on proposed full adders are finally demonstrated. The CPL 8-bit RCA and as well as the proposed ones is having better delay performance than the static CMOS and BBL-PT 8-bit RCA. The performance of the proposed BBL-PT cell with current sink & current source inverter structures are examined using PSPICE and the model parameters of a 0.13 µm CMOS process

Bio-inspired FPGA Architecture for Self-Calibration of an Image Compression Core based on Wavelet Transforms in Embedded Systems

A generic bio-inspired adaptive architecture for image compression suitable to be implemented in embedded systems is presented. The architecture allows the system to be tuned during its calibration phase. An evolutionary algorithm is responsible of making the system evolve towards the required performance. A prototype has been implemented in a Xilinx Virtex-5 FPGA featuring an adaptive wavelet transform core directed at improving image compression for specific types of images. An Evolution Strategy has been chosen as the search algorithm and its typical genetic operators adapted to allow for a hardware friendly implementation. HW/SW partitioning issues are also considered after a high level description of the algorithm is profiled which validates the proposed resource allocation in the device fabric. To check the robustness of the system and its adaptation capabilities, different types of images have been selected as validation patterns. A direct application of such a system is its deployment in an unknown environment during design time, letting the calibration phase adjust the system parameters so that it performs efcient image compression. Also, this prototype implementation may serve as an accelerator for the automatic design of evolved transform coefficients which are later on synthesized and implemented in a non-adaptive system in the final implementation device, whether it is a HW or SW based computing device. The architecture has been built in a modular way so that it can be easily extended to adapt other types of image processing cores. Details on this pluggable component point of view are also given in the paper

Multi-level Failure, Causality and Hazard Insights via Knowledge Based Systems

PresentationOver many decades there has been a significant development of knowledge-based, intelligent design tools and their use in the design of process systems. Amongst such tools are “intelligent” piping and instrumentation (P&IDs) design environments, coupled to life cycle design environments. These tools can provide opportunities for the development of new, more efficient and re-usable approaches to hazard identification and diagnostic systems. They leverage modern information technology characteristics of such design environments. These considerations are part of a growing trend in industrial digitalization, as reflected in such initiatives as Industry 4.0 in Europe and driven by the Industrial Internet of Things (IIoT). Within this larger industrial digitalization picture, this work discusses the principles, developments and application of a hazard identification methodology (BLHAZID) that exploits structured representations of the design in the form of ISO15926 data standards. The hazard identification methodology is based in knowledge representations of failure modes of equipment types that are found in many process designs and how those failures subsequently affect the system states and other components. The underlying causal models can be used at various levels of aggregation, model fidelity and component inclusion detail. The aggregation can span across the most detailed view at the smallest component level through subsystem level to plant level perspectives. The ability to represent and then display failure causation and implications at different levels of granularity allows deeper insight into system failures, and the potential for real-time diagnostic deployment. The importance of failure and subsequent propagation prevention through the use of safety instrumented systems and other barrier devices is possible. Outcomes can be visualized in informative ways. The presentation will discuss these intelligent information technology approaches via some a case study, highlighting the advantages and challenges such approaches bring to hazard identification as well as highlighting other application areas such as real-time diagnosis, corporate knowledge capture of failures, operator training and accident investigation

A Method for Evaluating Manufacturing Change in Engineering Design

Design changes are a frequent occurrence over the life of a product that may be initiated by an update to the product functionality, new customer needs, or generational improvements. The costs associated with these changes are undesirable, and are often times greatly inflated by additional, unanticipated changes that result from change propagating throughout the system. Propagation paths occur when an initiating change to a component necessitates subsequent changes to coupled components, as the change continues to propagate throughout the product architecture. The nature of this change propagation is challenging to characterize and accurately predict. To address this issue, a change prediction method is developed that builds upon current change management strategies. The method is comprised of: (1) a design structure matrix (DSM) to model the relationships and connectivity within a system, (2) coupling index (CI) values (ranging from 0 to 1) that assess the likeliness of a change to one component/feature affecting another, and (3) design for manufacturing (DFM) information to provide an estimate of the cost and impact of a change. The method can either be applied at the component level, or through further decomposition, at the interfacing feature level. Modeling the relationships between interfacing features, as opposed to components, offers a more detailed representation of change, but requires more knowledge of the system that may not be available in the earlier stages of design. When evaluating a propagation path, the coupling index values are multiplied together as the path extends, to produce a decreased probability for higher orders of coupling. The proposed change prediction method is applied on three industry examples: BMW X5 headliner and center console assemblies, and a Ryobi drill assembly. The method is shown to produce viable results that allow for informed decisions during change management. These results show that the objective measures of coupling and manufacturing cost of change are effective approximations. A comparison of the results from the component and feature based methods show that a feature level analysis offers improvements in accuracy, and sensitivity to uncertainty and path representation. Furthermore, the method proves to be a valuable tool during the initial design of a product, as it can be used to identify features, interfaces, and manufacturing types that will lower a product\u27s overall ease of change

Augmenting High-Level Petri Nets to Support GALS Distributed Embedded Systems Specification

Part 9: Embedded Systems and Petri NetsInternational audienceHigh-level Petri net classes are suited to specify concurrent processes with emphasis both in control and data processing, making them appropriate to specify distributed embedded systems (DES). Embedded systems components are usually synchronous, which means that DES can be seen as Globally-Asynchronous Locally-Synchronous (GALS) systems. This paper proposes to include in high-level Petri nets a set of concepts already introduced for low-level Petri nets allowing the specification of GALS systems, namely time domains, test arcs and priorities. Additionally, this paper proposes external messages and three types of (high-level) asynchronous communication channels, to specify the interaction between distributed components based on message exchange. With these extensions, GALS-DES can be specified using high-level Petri nets. The resulting models include the specification of each component with well-defined boundaries and interface, and also the explicit specification of the asynchronous interaction between components. These models will be used not only to specify the system behavior, but also to be the input for model-checking tools (supporting its verification) and automatic code generation tools (supporting its implementation in software and hardware platforms), giving a contribution to the model-based development approach and hardware-software co-design of DES based on high-level Petri nets

Feature-based representation for assembly modelling

The need for a product model which can support the modelling requirements of a broad range of applications leads to the application of a feature-based model. An important requirement in feature-based design and manufacture is that a single feature representation should be capable of supporting a number of different applications. The capability of representing products composed of assemblies is seen to be necessary to serve the information needs of those applications. To achieve this aim it is an essential prerequisite to develop a formal structure for the representation of assembly information in a feature-based design system. This research addresses two basic questions related to the lack of a unified definition for features and the problem of representing assemblies in a feature-based representation. The intention is to extend the concept of designing with features by incorporating assembly information in addition to the geometrical and topological details of component parts. This allows models to be assembled using the assembly information within the feature definitions. Features in this research are defined as machined volumes which are represented in a hierarchical taxonomy. The taxonomy includes several types and profiles of features which cover a general range of machined parts. A hierarchical assembly structure is also defined in which features form basic entities in the assembly. Each feature includes information needed to establish assembly relationships among features in the form of mating relationships. An analysis of typical assemblies shows that assembly interfaces occur at the face level of the mating features and between features themselves. Three mating relationships between pairs of features have been defined (against, fits and align) and are represented in the form of expressions that can be used for evaluations. Various sub-types of these major mating relationships can be identified (e.g. tight fit, clearance fit, etc.) and represented through the use of qualifying attributes. Component Relation Graphs, Feature Relation Graphs and Face Mating Graphs have been developed to represent each level of interaction in an assembly, and assembly relationships are combined with knowledge on process planning into a Component Connectivity Graph. These graphs are used as the basis for deriving an integrated data structure which is used for defining classes for each level in the assembly hierarchy. The implementation of a prototype system has been facilitated by use of an object-oriented programming technique which provides a natural method of adding functionality to the geometric reasoning process of features and the complex relationships between the parts that make up the assembly. The feature-based model is embedded in an object-oriented solid modeller kernel, ACIS®. The research demonstrates the possibilities for a single feature representation to support multiple activities within a computer integrated manufacturing environment. Such a representation can form the basis of design improvement techniques and manufacturing planning as well as be a model to support the life cycle of the product