Showing papers presented at "AUTOTESTCON in 1995"

Automated functional test generation

Abstract: The paper describes a new process for automating and controlling functional software testing, using a model of an application's desired behavior. The technology, known as Model Reference Technology, or MRT, is described. The process used to build a model and generate tests is explained and examples given. Samples of the results obtained by Cadence Design Systems using production applications of this technology are included.

Automated fault detection and identification using a fuzzy-wavelet analysis technique

Abstract: A new method is proposed for fault detection and identification in complex systems The technique of Fuzzy Wavelet Analysis is introduced which uses a fuzzified wavelet transform to analyze wide bandwidth fault features A special attribute of this tool is its ability to employ localized time/frequency analysis of fuzzy data for fault detection and identification purposes Performance measures of detectability and identifiability are defined to assist in assessing the performance of the algorithm Performance improvement is achieved through a learning mechanism based on the detectability and identifiability measures A fuzzy similarity measure is also introduced to reduce sensitivity to noise The algorithm uses both on-line and off-line learning for designing and updating the rulebase

Non-intrusive built-in self-test for FPGA and MCM applications

Abstract: Built-In Self-Test (BIST) techniques which are non-intrusive to the circuitry under test are investigated for incorporation in Field Programmable Gate Arrays (FPGAs) and Multi-Chip Modules (MCMs) The purpose is to test and diagnose circuitry external to the FPGAs or the various VLSI devices on MCMs during off-line system level testing These approaches incur no area or performance penalties yet diagnostic resolution can be obtained to the device level Design guidelines are developed to assist in the effective application and implementation of these techniques

Sequential test strategies for multiple fault isolation

Abstract: In this paper, we consider the problem of constructing near-optimal test sequencing algorithms for diagnosing multiple faults in redundant (fault-tolerant) systems. The computational complexity of solving the optimal multiple-fault isolation problem is super-exponential, that is, it is much more difficult than the single-fault isolation problem, which, by itself, is NP-hard. By employing concepts from information theory and Lagrangian relaxation, we present several static and dynamic (on-line or interactive) test sequencing algorithms for the multiple fault isolation problem that provide a trade-off between the degree of suboptimality and computational complexity. Furthermore, we present novel diagnostic strategies that generate a static diagnostic directed graph (digraph), instead of a static diagnostic tree, for multiple fault diagnosis. Using this approach, the storage complexity of the overall diagnostic strategy reduces substantially. Computational results based on real-world systems indicate that the size of a static multiple fault strategy is strictly related to the structure of the system, and that the use of an on-line multiple fault strategy can diagnose faults in systems with as many as 10,000 failure sources.

On-line inspection of surface mount devices using vision and infrared sensors

Abstract: This paper introduces a methodology for online inspection of surface mount components using vision and infrared sensors. The complementary nature of vision and infrared sensors allows for separation of solder joint defects into surface level defects and solder mass related defects for defect detection. The vision sensor can provide reliable information for surface level defects while infrared sensors are capable of providing information about solder mass related defects. An experimental facility is described and software routines developed for defect defection. Using both oblique and flat illumination techniques, the 2-dimensional gray scale images of the printed circuit boards are captured and preprocessed for suitable feature extraction. A sampling scheme has been developed for infrared inspection to reduce the inspection time. For defect detection a neural network construct is used to compare incoming data with stored templates. In addition, a classifier based on fuzzy relations and linguistic labels has been used to perform classification of linear misalignment defect accommodating the uncertainty associated with it. The strategy is demonstrated with inspection of a number of solder joint defects.

Nondestructive reverse engineering of trace maps in multilayered PCBs

Abstract: The focus of this paper is on separating the layers of an unpopulated, two layered circuit card assemblies/printed circuit boards (CCA/PCB) using X-ray stereo imaging. By separating the layers, we mean that our desire is to separate the traces on each layer of any multi-layered CCA. The final end product is envisioned to be an interactive, automated trace reconstruction system which will separate individual trace layers on a multi-layered PCB. Some of the benefits of such a system are: (1) eliminates the need to have prior knowledge of the CCA via examination of its engineering data; (2) the system can be generalized to different types of CCA's which have different number of trace layers, without any modification to the software; (3) allow the examination of each trace layer of a (multi-layered) CCA separately; (4) a non-intrusive technique which would not subject the CCA to any electronic stimulation.

Built-in test maturation concepts using test program set and relational database technologies

Abstract: Continual improvement of avionic built-in test (BIT) is critical to mission readiness and capability. This paper discusses how test program set (TPS) and relational database (RDB) technologies can be used for this purpose. Important aspects for continually improving avionic BIT and TPS operation are discussed.

Recasting the avionic support paradigm

Abstract: Cost and performance problems associated with the current avionic support paradigm, which had its origins in the 1960s and is based largely on TPS/ATS technology, would suggest that a fundamental change in paradigm should be considered A new paradigm, that more closely integrates the mission related and support related aspects of both acquisition and development, could resolve many chronic deficiencies while being more compatible with evolving prime system technology

A view of the ABBET upper layers

Abstract: Currently, the IEEE Std 1226-1993 (ABBET) is undergoing significant revision in preparation for its release as a "full-use" standard Much of this work is motivated by a need to define the interfaces between the various "layers" of the current architecture and prepare a road map for implementing those interfaces To date, little work has been-done on the upper layers of ABBET, yet it is believed that the upper layers offer the greatest potential for cost savings in developing advanced automatic test systems In this paper, we address the issues of the ABBET upper layers in the context of a new architecture that is focused on addressing the needs of the upper layers

A comparison of conventional and inference model based TPS development processes

Abstract: Many claims have been made regarding the benefits of applying inference model (i.e., dependency model) technology to the development of Test Program Sets. However, although this technology has been around for over a decade, it does not enjoy widespread acceptance in the TPS community. If inference model technology is ever to realize its full potential, the barriers to its incorporation into the TPS process must be identified and overcome. This paper compares the conventional and inference model based TPS development processes and highlights some of the more formidable problems of the inference model approach.

SEDACS-a client/server approach to TPS development

Abstract: The C-17 Support Equipment Data Acquisition and Control System (SEDACS) Test Program Set/Test Requirements Document (TPS/TRD) development system was upgraded from a host-based Honeywell/Multics mainframe system to a new client/server system with Internet connectivity Reliability, flexibility, and supportability were the requirements for the new system The combination of the client/server model and commercial software met these requirements by exploiting fast and inexpensive hardware and commercial off-the-shelf (COTS) software such as word processing and project and circuit analysis software Greater efficiencies were realized by reducing the required time needed to train users, develop TPSs, and prepare supporting documentation Quality was improved by incorporating configuration management tools and integrated spell checking into the applications suite and by designing around a centralized database This paper briefly describes how we developed our new system and how we migrated from our existing mainframe (or legacy) system to a client/server system

A path to superior testing in the 21st century

Abstract: Reaching the 21st century with superior test tools will require serious attention to three areas which are often under-emphasized in automatic test system (ATS) development the needs of users, powerful user interfaces, and data collection. When the needs of the various users are understood, a properly designed interface can be created which provides simple access to the test system functionality required to meet those needs. Keeping track of system performance and changes in the users' needs after a system is fielded must be an early design consideration to keep the user satisfied throughout the life of the system. This paper addresses the needs of users including technicians, software developers, software maintainers, and system engineers, with an emphasis on technicians. We discuss control and information presentation features which can be used to build a powerful user interface for test. Local maintenance data collection, creation and review of operator notes, and focal processing and analysis on automatic test systems can provide useful management tools in the maintenance environment. Such tools can help solve many data accuracy problems which now exist in large databases. These data collection concepts can get the users involved, improve maintenance data accuracy, and be a valuable source of operator feedback to software maintainers.

Integrated diagnostic and repair information system (IDRIS)-an open system approach

Abstract: The IDRIS successfully established the proof-of-concept that easy-to-use software can be developed to integrate advanced test, diagnostics, communication, and maintenance software packages by creating an intuitive user interface to manage the complex software interfaces Tests of IDRIS demonstrated that automating more of the complete maintenance procedure is possible and that can directly correlate to a decrease in the system's mean time to repair (MTTR) A lower MTTR is one step toward simultaneously increasing the operational readiness and decreasing the life-cycle cost

Electro-optical test collimators for real world systems

Abstract: The requirements for current and future EO system test equipment demands down-sized, multi-functional, multi-spectral, lightweight, low-cost Test Collimators. Last year's Autotestcon '94 paper titled "Down-Size Multi-Functionar EO Test Collimators" presented the Hughes Test Collimator approach of an all-metal, reflective mirror assembly, combined with an integrated target assembly, utilizing the emissivity target and other Hughes patented technologies. This year's paper will present additional technologies and capabilities, quantify measured performance results, elaborate on many of the advantages of the Hughes approach, and emphasize the multi-system, multi-functional capability.

Dependency modeling as an input to MIL-STD TRD/TPS development

Abstract: There are a number of dependency modeling tools in use today. The concept of representing the relationship between system behavior and failure modes using dependency modeling (otherwise called inference modeling) has significant merit, and has been proven to help achieve improved testability at reasonable cost. The purpose of this paper is to establish the requirements for dependency modeling systems which would result in optimum effectiveness of the output for the development of Test Requirements Documents and Test Program Sets.

Using dependency analysis to predict fault dictionary effectiveness

Abstract: A case study was performed to determine how fault isolation ambiguity groups for electronic systems can be predicted. The baseline method for fault isolation was the fault dictionary based on fault simulation. Several predictors were investigated: a simplified fault dictionary with a detect limit of only 1, dependency analysis, and intersections of cones of logic that feed erroneous outputs. Dependency analysis (based on a hierarchical logic model) and the simplified fault dictionary both produced fault isolation statistics that closely approximated those of the full fault dictionary. Cones of logic did not generate useful fault isolation results.

An approach to reducing maintenance and development costs of complex support equipment

Abstract: The US Air Force and Pratt and Whitney P&W are teaming to meet the challenges of a tighter defense budget The Field Reprogramming System (FRS) and the On-Wing Electronic Engine Control Reprogramming System (OWERS) are examples of how this team was able to reduce maintenance and developmental costs of support equipment while providing improved support to F15, F16, and C-17 aircraft

Modeling diagnostic constraints with AI-ESTATE

Abstract: The Artificial Intelligence and Expert System Tie to Automatic Test Equipment (AI-ESTATE) subcommittee of the IEEE Standards Coordinating Committee 20 (SCC20) has been developing a set of standards for exchanging diagnostic knowledge in intelligent test systems. To date, AI-ESTATE has developed models for fault trees and enhanced diagnostic inference models (EDIMs). Since the start of committee work, it was believed that AI-ESTATE needed to address the issue of defining constraint knowledge, which could be used to guide and refine diagnostics. In this paper, we discuss early efforts by AI-ESTATE to define such a constraint model.

Visual reverse engineering using SPNs for automated testing and diagnosis of digital circuits

Abstract: This paper presents a new methodology, which leads to the development of a prototype system for the automated testing and faults diagnosis of digital circuits The methodology presented here is based on an automated visual reverse engineering process, which assists the extraction of the functional behavior of a digital circuit and for the detection and diagnosis of faults and defects on it The visual information extracted from a PCB (printed circuit board) or a digital circuit is represented by SPN (stochastic Petri-net) forms in order to maintain both its structural and functional characteristics

Test synthesis: an innovative approach to analog and system testability analysis using state dependent flow diagrams

Abstract: The largest single effort associated with a testability analysis is the creation or modeling of tests This paper presents a methodology, referred to as Test Synthesis, that automates the process of creating a set of tests that are suitable for performing a testability analysis and developing an initial test strategy In the context of this paper, a test is defined as: "The acquisition or definition of data that leads to the detection of one or more faults" Test Synthesis combines topological data with testability models to create a comprehensive set of tests with minimal user input

Bridging fault simulation using Iddq, logic, and delay testing

Abstract: Accepted integrated circuit verification techniques involve stuck-at fault simulation However, it has been shown that the majority of actual physical faults in the faulty integrated circuit are bridging faults For this reason, the interest in bridging fault simulation techniques have increase One characteristic with bridging faults is that the bridging fault may have electrical as well as logical behavior This characteristic makes detection of bridging faults more difficult and this characteristic increases the complexity of bridging fault simulation The three techniques most widely used for bridging fault simulation are current testing, stuck-at testing, and delay testing This paper compares the complexity and robustness of the three techniques and new developments in the three techniques Results show the current testing technique to be the most robust and have the lowest complexity which approaches stuck-at fault simulation complexity

C-17 TPS development strategy

Abstract: This paper describes key elements and issues commonly associated with test program set (TPS) development. The information is intended to provide guidelines for successful implementation and management of a TPS development project. This topic has been divided into two major categories: development environment and engineering implementation. The development environment section focuses on the goals and tasks that need to be addressed when planning a TPS project. These include strategic planning, staffing, scheduling, identifying the necessary engineering development tools, and establishing development procedures for commonality among TPSs. The engineering implementation section addresses the development processes that produce the required products. These include derivation of the test requirements for the unit under test (UUT), development of a UUT test strategy, hardware and software design and integration, product delivery, and customer support. The information presented is based upon experience with numerous TPS programs, including the successes achieved by McDonnell Douglas in concurrent aircraft/TPS development for the United States Air Force's new C-17 Globemaster III transport aircraft.

C-17 automatic test system operation strategies for integrated air vehicle and support system deployment

Abstract: Weapon systems are typically developed and upgraded in phases, where support system definition and implementation are completed after air vehicle deliveries commence. It can be several years before the automatic test system (ATS) is fully operational and self-supporting. C-17 Globemaster III deployment requirements however, dictated that the support system be delivered in a fully operational state to provide avionics repair capability concurrent with the first aircraft delivery. This demanding requirement necessitated innovations in program management, support system design, deployment, field operations, and support. This paper discusses the deployment and field operation. Strategies implemented and lessons learned by the MDA/USAF integrated product team to achieve an industry first in integrated weapon system activation.

Smart E-O targets as versatile, self-contained instruments

Abstract: Current Electro-Optical (E-O) testing requirements have demanded a shift to reduced cost, off-the-shelf technology. While Hughes Technical Services Company (HTSC) has worked toward developing downsized collimators to meet this demand, this proves to be only part of the solution. Highly versatile, self-contained, replaceable E-O targets are also required to meet this need. The Depot and Test Systems Division within HTSC has developed a standard for replaceable E-O targets. These Integrated Target Assemblies (ITA) must test such various systems as: FLIR, Near Infrared (NIR) tracker, Visual Telescope, TV Video, and Laser LRF/LTD. Smart targets have been designed which are interchangeable; can perform built in tests (BITs); contain their own calibration data stored electronically; correct their performance using sophisticated DSP algorithms; as well as automatically correct their own boresight alignment. A suite of such targets would be invisible to the user and would act in concert as versatile instruments containing all the functionality required for testing any number of prime systems.

Hierarchical built-in test: an alternative test and repair strategy

Abstract: This paper looks at the capabilities of Built-in Test (BIT) at various levels of assembly (disassembly) and will examine how strategies can be developed to locate and diagnose faults without the need for external automated test equipment (ATE). Various test stages will be considered for both manufacturing and maintenance. It will be shown how hierarchical BIT can ensure that faults are diagnosed at the most appropriate level of repair: system, board, or IC. This capability will in turn create a flexibility in repair strategies, with component level repair possible even by end users.

CASS CTS overview

Abstract: The CASS CTS provides a standard ATE system for use in meeting the unique needs of guided munitions testing. These munitions often require real-time, asynchronous stimuli and responses across multiple interfaces to simulate real-world operation. The CTS is designed to meet the technical challenges inherent in testing guided munitions while in factory, depot, or weapons station environments.

A protocol for controlling devices over a network-a new VXIbus draft specification

Abstract: This paper describes the TCP/IP Instrument Protocol Specification and its companion document, the TCP/IP-VXIbus Interface Specification. These documents are draft VXIbus Consortium specifications which define a protocol for connecting VXIbus instrumentation to a TCP/IP computer network. These specifications begin to fill the need for standard ways to connect instrumentation to computer networks. This paper describes the objectives of the specifications, gives a brief LAN primer to assist in understanding the technology, and describes both the network instrument protocol and the LAN-to-VXI mapping to be implemented within TCP/IP-VXIbus Interface Devices.

The ATLAS language-panacea or pariah? Does it only specify the task or does it really drive the tester?

Abstract: ATLAS is a language intended to be used for the specification of test equipment independent and transportable test programs. Despite the significant amount of effort put into revising and updating the ATLAS standards over the last 25 years, the language is still only used when mandated and is not the automatic choice of engineers. This article discusses the reasons for this and looks at the future development of ATLAS.

Test software at Texas Instruments: what SEI level is appropriate?

Abstract: In 1989, Texas Instruments (TI) as a corporation embarked on an aggressive mission to improve the quality of its internally developed software. As a part of this ongoing effort, the Test Engineering Department of the Defense Systems and Electronics Group (DSEG) evaluated existing test software development practices and procedures. Using the Software Engineering Institute's (SEI) Capability Maturity Model (CMM) to measure software process quality, DSEG Test Engineering Department was internally appraised at SEI Level 2 and is currently working towards Level 3. There were unique challenges and difficulties relative to this achievement due to the wide diversity of test types, development standards, languages and platforms associated with test software. This paper presents the approach, schedule, lessons learned and some of the benefits which resulted from the efforts of the DSEG Test Engineering software quality thrust.

Commercial Off The Shelf (COTS)/Non Developmental Item (NDI) testing for Department of Defense using infra-red technology

Abstract: This paper presents solutions to the challenges facing Department of Defense testing of Commercial off the Shelf (COTS) and Non Developmental Items (NDI) The solution proposed is testing using thermal imaging technology Thermal imaging is a bold departure from traditional testing methodology such as Automatic Test Equipment (ATE) in conjunction with Test Program Sets (TPS) Such traditional testing methodology requires a certain amount of technical data However, with COTS and NDI commercial vendors may choose to not sell their technical data or, as is often the case, it is cost prohibitive for DoD to purchase the documentation and drawings Thermal imaging is ideal for DoD COTS and NDI testing and repair because it requires no technical data