System Integration Testing Research Articles

ATLAS LAr calorimeter performance in LHC run 2 and electronics upgrades for next runs

Liquid argon (LAr) sampling calorimeters are employed by ATLAS for all electromagnetic calorimetry in the pseudo-rapidity region |η|<3.2, and for hadronic and forward calorimetry in the region from |η|=1.5 to |η|=4.9. In the LHC Run 2 about 150 fb−1 of data at a center-of-mass energy of 13 TeV have been recorded. The well calibrated and highly granular LAr Calorimeter reached its design values both in energy measurement as well as in direction resolution. Electronics developments are pursued for the trigger readout of the ATLAS LAr Calorimeter towards the Phase-I upgrade scheduled in the LHC shut-down period between December 2018 and early 2021. Trigger signals with finer spatial granularity and higher precision are needed in order to improve the identification efficiencies of electrons, photons, taus, jets and missing energy, at high background rejection rates, already at the Level-1 trigger. Following new TDAQ buffering requirements and high expected radiation doses in the pileup conditions of the high-luminosity LHC, the LAr Calorimeter electronics will be further upgraded (Phase-II) to readout the full 182,500 calorimeter cells at 40 MHz with 16 bit dynamic range. Developments of low-power preamplifiers and shapers to meet these requirements are ongoing in 130 nm CMOS. In order to digitize the analogue signals on two gains after shaping, radiation-hard, low-power 40 MHz 14-bit ADCs are developed using a SAR architecture in 65 nm CMOS. This contribution gives an overview of the detector operation, changes in the monitoring and data quality procedures, to cope with increased pileup, as well as the achieved performance. Results of ASIC developments including quality assurance and quality control (QA/QC) and radiation hardness evaluations, performances of the pre-production boards and results of the system integration tests, progress of QA/QC of final production boards are presented along with the overall system design for the Phase-I upgrade. Results of tests of the first prototypes of front-end components are presented, along with design studies on the performance of the off-detector readout system for the Phase-II upgrade.

(Invited) Degradation Aspects of Electrocatalysts and Materials in PEM Water Electrolyzers

When coupled to renewable but nonetheless intermittent power sources such as wind or solar, polymer electrolyte membrane (PEM) electrolyzers are intended to be in operation for tens of thousands of hours [1]. Hence, the long-term behavior of catalyst coated membranes (CCMs) under some specific operating characteristics is of great importance. Previous durability studies have focused on electrolyzers operating at constant current input, showing little to no significant degradation (<4µVh) after 40.000 h at moderate conditions (25 cell stack, around 50°C and 1,3 A/cm²)[2]. In another study, constant and highly variable operation mode was compared for three used stacks after 7.500 h and indicated that variable operation might result in higher cell decay [3]. To the best of our knowledge, no durability data has been published yet, that fundamentally contrasts the effects of defined dynamic load profiles and constant operation on the cell decay in single cell tests. This is particularly crucial, since coupling PEM electrolysis to renewable power sources involves dealing with fluctuating power inputs, startup, and shutdown incidents that for PEM fuel cells are known to accelerate degradation. In this study we demonstrate for the first time, the different effect of a constant and defined dynamic operation on the cell decay. For this purpose, durability tests were performed using state-of-the-art PEM electrolysis cells. The physicochemical characteristics were comprehensively addressed and the main process constraints (e.g., electrical, reaction, and transport) were analyzed. Exceptional improvements could be demonstrated using new membrane and catalyst materials enhancing performance, gas separation, and overall durability. Our results also show an effect of the operation mode on the degradation rate. Moderate conditions of 1 A/cm² show no significant degradation after 1000h. This is in line with the above mentioned results for commercial electrolyzer units. At higher current densities significant degradation rates were found. This study undeniably suggests coupling PEM electrolyzers to intermittent power sources under long term operation, contributing to transformative knowledge in the field of energy conversion and storage. [1]. M. Carmo, D. Fritz, J. Mergel and D. Stolten, International Journal of Hydrogen Energy, 38, 4901-4934 (2013) [2] Katherine Ayers, presented at the DOE Fuel Cell Technologies Program Webinar, May 23, 2011 [3] 2013 Annual Merit Review Proceedings, II.A.2, Renewable Electrolysis Integrated Systems Development and Testing

The Phase-1 Trigger Readout Electronics Upgrade of the ATLAS Liquid Argon Calorimeter

Electronics developments are pursued for the trigger readout of the ATLAS Liquid-Argon Calorimeter towards the Phase-I upgrade scheduled in the LHC shut-down period of 2019-2020. The LAr Trigger Digitizer system will digitize 34,000 channels at a 40 MHz sampling with 12 bit precision after the bipolar shaper at the front-end system, and transmit to the LAr Digital Processing system in the back-end to extract the transverse energies. Results of ASIC developments including quality assurance and radiation hardness evaluations, performances of the nal prototypes and results of the system integration tests will be presented along with the overall system design.

Model-based test suite generation for graph transformation system using model simulation and search-based techniques

Abstract Context Test generation by model checking is a useful technique in model-based testing that allows automatic generation of test cases from models by utilizing the counter-examples/witnesses produced through a model checker. However, generating redundant test cases and state space explosion problem are two major obstacles to transfer this technique into industrial practice. Objective An idea to cope with these challenges consists in an intelligent model checking for exploring only a portion of the state space according to the test objectives. Motivated by this idea, we propose an approach that exploits meta-heuristic algorithms to adapt a model checker when used for integration testing of systems formally specified by graph transformations. Method This method is not based on model checking algorithms, but rather uses the modeling and simulation features of the underlying model checker. In the proposed approach, a population of test suites that each of which is a set of paths on the state space, is evolved towards satisfying the all def-use test objectives. Consequently, a test suite with high coverage is generated. Results To assess the efficiency of our approach, it is implemented in GROOVE, an open source toolset for designing and model checking graph transformation systems. Empirical results based on some case studies, confirm a significant improvement in terms of coverage, speed and memory usage, in comparison with the state of the art techniques. Conclusion Our analysis reveals that intelligent model checking can appropriately address the challenges of traditional model-checking-assisted testing. We further conclude that graph transformation specification is an efficient modeling solution to behavioral testing and graph transformation tools have a great potential for developing a model-based testing tool.

Stability of a Switched Mode Power Amplifier Interface for Power Hardware-in-the-Loop

Power hardware-in-the-loop (PHIL) is an attractive, real-time system testing and validation technique. Virtual models can be replaced with physical equipment to emulate system integration testing, and perform model validation without the cost and risk of a full scale power system. Power amplifiers are the principal components that facilitate the power interface between the physical and the virtual systems. This necessary interfacing introduces dynamics that do not exist in the real system and is the source of stability and accuracy issues affecting PHIL applications. This paper presents a stability analysis of a practical PHIL system based on the ideal transformer model interface algorithm that utilizes a voltage source converter for power amplification. A systematic approach to evaluate the expected stability characteristics of PHIL experiments is developed. The analysis in this paper shows that in a practical system, the power amplifier's filter, sampling, and measurement filtering are all shown to influence the stability in a counterintuitive way, leading to a nonmonotonic stability characteristic. An experimental PHIL platform based on a real-time digital simulator real-time computer has been used to validate the analysis and confirm the effects of the practical interface. Switching dead-time is also shown to have a significant stabilizing effect.

Testing of IEC 61850 sampled values based digital substation automation systems

With digital communication technologies continuing to grow in performance and reliability, a fully digital substation automation system (SAS) with a sampled values based process bus has become a realisable prospect in the foreseeable future. This, however, demands additional work in engineering configurations and tightens the existing constraints on multi-vendor interoperability, network performance and time synchronisation. As a result, detailed testing and validation of SASs prior to installation is paramount. Integrated testing is the most comprehensive approach to test a SAS, as it evaluates the performance of multiple aspects of the system simultaneously. Real-time power system simulators can interface with multiple intelligent electronic devices in real-time via IEC 61850 station and process buses, while accurately simulating the electrical substation. Hence, they possess the unique capability to carry out closed-loop, integrated testing of SASs. This study presents a methodology to test a fully digital SAS using a real-time power system simulator. Particular emphasis is given on carrying out integrated system testing of a SAS in a laboratory environment. Example test scenarios are provided to highlight the effectiveness of the proposed testing approach.

Development and Field Test of an Electric-Submersible-Pump Reliable-Power-Delivery System

Summary In high hydrogen sulfide (H2S) and high-pressure/high-temperature fields, the average run life of electric submersible pumps (ESPs) is limited to 3 years. Dismantle/inspection/failure-analysis (DIFA) results show that approximately 50% of ESP failures are directly or indirectly related to electrical-delivery problems concentrated approximately 200 ft in between the packer and the motor. This paper presents a collaborative research-and-development effort to develop and trial test a reliable-power-delivery system (RPDS) with the goal of extending the average ESP run life from the current 3 years to 10 years. The development focuses on improving reliabilities of key power-delivery components including packer penetrator, motor-lead-extension (MLE) cable, and cable connection to the motor. The design integrates learnings from advanced completion and subsea technology, and includes new concepts, features, and materials. Field-pressure-testable connections are implemented to ensure proper field-connections makeup. Factory testing incorporated a robust highly-accelerated-life-test (HALT) methodology to simulate a 10-year service life. Prototype components were designed, fabricated, and tested. These components were integrated and subjected to a rigorous system-integration test. After the comprehensive factory tests, a field-prototype system was built and installed in an offshore well. The system has been operated and exceeds the trial-test success criterion of a minimum 180-day run life. For years, ESP reliability has been a constant issue faced by the industry, with electrical problems at the center of many failure causes. This paper presents a completely new design approach to address this critical challenge. Field installation and testing show the potential of extended run life with this new power-delivery technology.

An emission management framework for implementing a large railway system with interface complexity

This paper presents a framework for a life cycleapproach electromagnetic compatibility (EMC) management to control the overall emission of the modern railway system to external environment. With a large number of electrical equipment interfaces following integration of mechanical and electrical subsystems, cooperation across all disciplines during system implementation through key EMC activities is described at each project development phase to guarantee the success of a large-scale project EMC safety assurance. A case study of a large Mass Rapid Transit project is examined to illustrate how the framework may be applied. The validation of safe railway system emission is demonstrated through positive system integration test results under EN 50121-2 criteria. The framework flexibility to accommodate foreseeable impacts of future change is also discussed.

Overview of U.S. Department of Energy Office of Fossil Energy’s Solid Oxide Fuel Cell Program

The primary mission of the U.S. Department of Energy’s Office of Fossil Energy (FE) is to ensure the nation can continue to rely on its indigenous fossil fuel resources for clean, secure, and affordable energy. A component of that effort is the Solid Oxide Fuel Cell (SOFC) Program, administered by FE’s National Energy Technology Laboratory (NETL). The SOFC Program is committed to: developing efficient, low-cost electricity from natural gas or coal with intrinsic carbon capture capabilities for distributed generation and central power generation applications; maintaining cell development and core technology research to increase the reliability, robustness, and durability of cell, stack, and system technology; and providing the technology base to permit cost-competitive distributed generation applications. The program recently initiated two focused efforts: addressing cell and system reliability and an Innovative Concepts initiative.Based on feedback from several program participants, chromium contamination of cathode was identified as a major contributor to performance degradation and reduced system reliability. NETL has launched an initiative to address the issue of chromium contamination. The SOFC Program portfolio presently has 13 projects addressing this critical issue.The SOFC Program is also funding an Innovative Concepts initiative that supports the research, development, and demonstration (RD&D) of SOFC technology that has the potential to surpass current anode supported planar SOFC technology in terms of cost and reliability. Program participants are developing novel cell and stack architectures and/or material sets. This next-generation SOFC technology development in the near-term includes nominally 5-10 kWe-scale stack tests using cells envisioned in the developer’s future commercial systems. The status of these strategically oriented research programs, along with the status of the program’s integrated systems tests and the roadmap to deploy a MWe-class natural gas-fueled distributed generation system, will be presented.

Evaluation on application of China Disease Prevention and Control Information System of Hydatid Disease II System integration and simulation tests

To report the integrated progress of the hydatid disease information management system, and to provide the reference for further system improvements by analysis of results on simulation test feedback. The work of institutional code matching by collecting fundamental and integrated information of the system in epidemic areas of hydatid disease was carried out, and professional control agencies were selected to carry out the simulation test. The results of agencies code matching at stage indicated the average completion rate was 94.30% on administrative agencies, 69.94% on registered professional agencies and 56.40% on professional institutions matching related to hydatid disease prevention and control implements in seven provinces (autonomous regions) and Xinjiang Production and Construction Corps. Meanwhile, the response rate of open-ended proposals was 93.33% on fifteen feedbacks, and the statistics showed 21.43% believed the system was low fluency, 64.29% considered the system was inconvenience for data inputs and 42.86% considered it would be improved on system statistics functions, of which 27.78% were provincial users, 22.22% were the city users and 50.00% were the county users. The hydatid disease prevention information management system meets the fundamental needs of the majority agencies in hyperendemic areas of echinococcosis, it needs to develop the further test with more agencies joining after the work of the institutional code matching completion and the system service improvement in the next stage.

Overview of U.S. Department of Energy Office of Fossil Energy’s Solid Oxide Fuel Cell Program

The U.S. Department of Energy Office of Fossil Energy (FE) National Energy Technology Laboratory (NETL) Solid Oxide Fuel Cell (SOFC) Program is committed to developing efficient, low-cost electricity from natural gas or coal with intrinsic carbon capture capabilities for distributed generation and central power generation applications; maintaining cell development and core technology research to increase the reliability, robustness, and durability of cell, stack, and system technology; and providing the technology base to permit cost-competitive distributed generation applications. Recent program efforts focused on addressing cell and system reliability (finding chromium contamination of the cathode a major contributor to performance degradation and reduced system reliability) and an Innovative Concepts initiative (developing novel cell and stack architectures and/or material sets). The status of these strategically oriented research programs, along with the status of the program’s integrated systems tests and the roadmap to deploy a MWe-class natural gas-fueled distributed generation system, will be presented.

틸트로터 무인기 비행제어컴퓨터 이중화 시스템 개발

틸트로터 무인기의 비행제어컴퓨터는 신뢰도 향상을 위하여 주 채널과 보조 채널을 갖는 이중화 시스템으로 설계되었다. 이중화 기능은 채널 전환과 데이터 복원으로 구성된다. 채널 전환 기능은 교차채널 데이터링크를 이용한 소프트웨어 방식과 워치독 타이머를 이용한 하드웨어 방식으로 구성되었다. 데이터 복원 기능은 운용 중 비행제어컴퓨터가 비정상적으로 재시작 되었을 때 비행 상태를 유지하기 위한 기능이다. 이중화 기능은 비행제어컴퓨터 벤치 시험, 체계 통합 시험 그리고 HILS 시험을 통해 검증되었다. 본 논문에서는 틸트로터 무인기 비행제어컴퓨터에 구현된 이중화 기능과 시험-검증 방법에 대해서 기술하였다. Flight control computer of tiltrotor UAV was designed by redundancy system with primary and secondary channels to improve reliability. The redundancy functions consist of channel switching and data recovery. The channel switching function consists of software method by using cross channel data link and hardware method by using watchdog timer. The data recovery is the function to maintain flight condition when the flight control computer is restarted exceptionally in operation. The redundancy system was verified by flight control computer bench test, system integration test and HILS test. This paper describes the redundancy function of tiltrotor UAV flight control computer and test-verification method.

SHPbench – A Smart Hybrid Prototyping Based Environment for Early Testing, Verification and (user based) Validation of Advanced Driver Assistant Systems of Cars

Statistical analysis show that more than 90 percent of all car accidents result from human mistakes. Advanced Driver Assistant Systems (ADAS) are intended to support and assist the car driver, and therefore contribute significantly to the reduction of accidents. ADAS become more and more complex and demanding regarding hard- and software fulfilling the requirements applied onto assistant systems nowadays and in the future. They have to be considered as multi-functional multi-domain mechatronic systems. Smart Hybrid Prototyping (SHP) is a by now proven approach for handling ADAS’ demands during and to the development process, specifically for early integrated component and system testing, its verification and validation with the focus on the interaction with the driver can only be reasonably and economically met by utilizing the SHP technology. For those mentioned purposes the SHPbench, an integrated development and validation environment, has been recently developed. The SHPbench's architecture and specification is presented and evaluated by applying a representative use case of an ADAS development process. This paper documents the use case setup, process steps and test results.

Analytical Stability Analogue for a Single-Phase Natural-Circulation Loop

Numerical solutions for transient fluid flow in nuclear systems often suffer from the effects of numerical diffusion and damping making the assessment of system stability rather difficult. Efforts for coping with this problem include research and development of algorithms with improved fidelity for stability calculations as they apply to particular problems. Benchmarking exercises in comparison with specially designed experiments are necessary to verify algorithmic fidelity and guide the development and adjustments of the algorithms. In this paper, an analytical approach is introduced where a simple model—an analogue—is constructed such that the basic instability mechanisms are represented in a form that lends itself to analytical solutions that are free from the diffusion and damping problems that plague finite volume algorithms. Direct conclusions can be made regarding the stability of a system in the case where the analogue closely resembles the system under study. However, when the system is too complex for direct assessment, the stability fidelity of numerical solutions can be assessed by comparing the numerical solution for the simple system with the analytical solution and using the comparison to quantify any damping effects and justify the application of the numerical method to the complex representation of the real system under study. The theoretical analysis is supported by reference to recent test data in the NuScale Integral System Test (NIST) facility representing a scaled-down NuScale module.

Applying A3 problem resolution to new system design to improve performance and reduce rework

AbstractThere is a need for constant improvement in today's projects/technology to stay competitive in the Oil and Gas market. This motivates actors in this domain to constantly anticipate the need for new products through innovation and development efforts that result in advanced subsea products. One such product is the Subsea Gas Compression module (SGC), the first installation of its kind. Aker Solutions has worked on standardizing Subsea Production Systems (SPS) and developed a quality system to fit these projects. When initiating new product development, Aker Solutions needs to adapt their quality system to define work processes suitable for an innovative project, which may demand other focus areas than for a traditional Major Subsea Project. At the time SGC project execution reached System Integration Testing (SIT) several errors were discovered. Some of these were attributed to late life design changes, multidisciplinary complexity and poor application of the Project Execution Model (PEM). This paper explores the SGC project from a retrospective viewpoint, investigating errors discovered during SIT by performing Root Cause Analysis, and recommends, based on the results, that the company updates the PEM with targeted activities for new product development to improve performance and reduce rework during later stages of development.

Design and Development of a Hand Exoskeleton Robot for Active and Passive Rehabilitation

The present work, which describes the mechatronic design and development of a novel rehabilitation robotic exoskeleton hand, aims to present a solution for neuromusculoskeletal rehabilitation. It presents a full range of motion for all hand phalanges and was specifically designed to carry out position and force-position control for passive and active rehabilitation routines. System integration and preliminary clinical tests are also presented.

Preliminary Design of a Robotic System for Catching and Storing Fresh Market Apples

Abstract: This paper presents the preliminary design of a two-link planar manipulator for fresh market apple catching. Rather than use the harvesting manipulator to place picked apples in a storage container, the secondary system catches and stores apples at the point of fruit separation in order to minimize path length and improve cycle time. Monte Carlo simulations were used to select link lengths and joint limits. The design includes two low cost stepper motors and a vacuum assisted end-effector. After fabrication, laboratory studies were conducted to measure the system’s repeatability and validate the proof-of-concept. A conservative estimate of repeatability is 20 mm, which is within the catching end-effector’s effective workspace. During integrated system testing in the lab, the secondary system caught all harvested fruit. Likewise, the pick-and-catch technique resulted in an approximately 50 percent reduction in overall cycle time compared to the conventional pick-and-place method. Future work will include development of an end-effector prototype with soft elements to minimize fruit bruising.

Enumerating message paths for interaction testing of object-oriented systems

MM path is integration artifact of object-oriented systems and is characterized by interleaved sequence of messages and method execution paths. In the context of UML sequence diagrams, an MM path is usually found common in many message paths and concatenation of one MM path with different MM paths results in distinct message paths. Adequate testing of all message paths in UML sequence diagrams implies the coverage of all possible concatenation of constituent MM paths in different object-states, which may not be fully achieved in practical situations. With limited test effort, practitioners are compelled to consider a subset of all message paths in ad-hoc manner or priority basis. It can be possible that the selected paths may not include at least one instance of highly critical MM path, whereas less critical MM paths may have been included with multiple instances. It is, therefore, necessary that the selected message paths would contain one instance of all MM paths and their additional instances as per their priorities. To address this problem, we propose two coverage criteria: all MM paths and prioritized MM paths and an MM path-based coverage model. To obtain such coverage model, we build a graph model called as sequence integration graph from the sequence diagram and thereafter, synthesize MM paths to merge them into a set of connected trees. Further, we capture priority information of the MM paths by means of edge weights and order of concatenation among the MM paths by means of connector edges between the trees. These information captured in the MM coverage model helps to determine effective coverage of the MM paths. Our experimental results substantiate usefulness of our MM path-based coverage model for selecting message paths to satisfy all MM paths and prioritized MM paths coverage criteria in the context of integration testing of object-oriented systems with the limited testing effort.

Off-Nominal Component Performance in a Supercritical Carbon Dioxide Brayton Cycle

Bechtel Marine Propulsion Corporation (BMPC) is testing a supercritical carbon dioxide (sCO2) Brayton system at the Bettis Atomic Power Laboratory. The integrated system test (IST) is a simple recuperated closed Brayton cycle with a variable-speed turbine-driven compressor and a constant-speed turbine-driven generator using sCO2 as the working fluid designed to output 100 kWe. The main focus of the IST is to demonstrate operational, control, and performance characteristics of an sCO2 Brayton power cycle over a wide range of conditions. Therefore, the IST was designed to operate in a configuration and at conditions that support demonstrating the controllability of the closed sCO2 Brayton cycle. Operating at high system efficiency and meeting a specified efficiency target are not requirements of the IST. However, efficiency is a primary driver for many commercial applications of sCO2 power cycles. This paper uses operational data to evaluate component off-nominal performance and predict that design system operation would be achievable.

Integration testing of heterotic systems.

Computational theory and practice generally focus on single-paradigm systems, but relatively little is known about how best to combine components based on radically different approaches (e.g. silicon chips and wetware) into a single coherent system. In particular, while testing strategies for single-technology artefacts are generally well developed, it is unclear at present how to perform integration testing on heterotic systems: can we develop a test-set generation strategy for checking whether specified behaviours emerge (and unwanted behaviours do not) when components based on radically different technologies are combined within a single system? In this paper, we describe an approach to modelling multi-technology heterotic systems using a general-purpose formal specification strategy based on Eilenberg's X-machine model of computation. We show how this approach can be used to represent disparate technologies within a single framework, and propose a strategy for using these formal models for automatic heterotic test-set generation. We illustrate our approach by showing how to derive a test set for a heterotic system combining an X-machine-based device with a cell-based P system (membrane system).