Laboratory Test Bed Research Articles

Identifying Unseen Faults for Smart Buildings by Incorporating Expert Knowledge With Data

Thanks to the development of sensor networks and information technology, data-driven fault detection and diagnosis (FDD) is getting more and more popular with rich data. In the building FDD field, mature supervised learning algorithms and strategies have been applied to detect and diagnose known faults. However, it is out of the question to collect labeled training data for every possible fault. Thus, there is a necessity to study FDD when the training data for some faults are unavailable. To the authors’ best knowledge, few works have reported how to identify “unseen faults.” In this paper, authors propose a novel expert knowledge-based unseen fault identification (EK-UFI) method to identify unseen faults by employing the similarities between known faults and unknown faults. The similarity is captured by incorporating essential expert knowledge that is encoded in the fault gene matrix. The fault gene is integrated with a latent incorporation matrix that transfers knowledge from known faults to unseen faults. With application to a real system, the proposed method is proven to be effective in identifying various building unknown faults with a high accuracy. Note to Practitioners — FDD is of great importance for saving energy and improving occupancy comfort levels and building safety levels. Identifying unseen faults in real application is challenging since: 1) building faults are complicated and confusing while well-labeled fault data is rare; 2) experimental fault data collected in laboratory test beds cannot be directly used as judgment criteria for real buildings; and 3) it is impossible to measure every possible fault ahead of time. Although supervised learning methods have been successfully applied in existing works to solve the building FDD, they could not attack the UFI problem. In this paper, a novel EK-UFI method is proposed to identify unseen faults by employing the similarities between known faults and unknown faults. Experimental results show that the proposed method is essential.

Cylinder Specific Pressure Predictions for Advanced Dual Fuel Compression Ignition Engines Utilizing a Two-Stage Functional Data Analysis

In-cylinder pressure is a critical metric that is used to characterize the combustion process of engines. While this variable is measured on many laboratory test beds, in-cylinder pressure transducers are not common on production engines. As such, accurate methods of predicting the cylinder pressure have been developed both for modeling and control efforts. This work examines a cylinder-specific pressure model for a dual fuel compression ignition engine. This model links the key engine input variables to the critical engine outputs including indicated mean effective pressure (IMEP) and peak pressure. To identify the specific impact of each operating parameter on the pressure trace, a surrogate model was produced based on a functional Gaussian process (GP) regression approach. The pressure trace is modeled as a function of the operating parameters, and a two-stage estimation procedure is introduced to overcome various computational challenges. This modeling method is compared to a commercial dual fuel combustion model and shown to be more accurate and less computationally intensive.

Increasing LPWAN Scalability by Means of Concurrent Multiband IoT Technologies: An Industry 4.0 Use Case

One of the most important challenges of the Internet of Things (IoT) in the next years will be the smooth incorporation of millions of smart devices into its communications paradigm. The greater coverage area of sub-1-GHz low-power wide area networks (LPWANs) makes them a suitable technology to easily encompass hundreds of end devices under a single base station. However, LPWAN inherent simplicity affects negatively on scalability, as these networks are not flexible enough to deal with a high number of nodes unless their traffic load is really low, which limits many potential use-cases. This paper analyzes the scalability issue in LPWAN and proposes the INTER-HARE protocol: a solution based on the use of concurrent multiband IoT technologies, where an 868-MHz LPWAN acts as transparent backhaul for a set of subnetworks working at 2.4 GHz. The implementation of the INTER-HARE protocol on a real IoT platform was assessed both in several laboratory testbeds and in a pilot developed in the premises of an industrial company, proving its suitability in non-delay sensitive monitoring applications with end devices scattered throughout the targeted area.

ТЕРАГЕРЦОВІ ТЕХНОЛОГІЇ В ТЕЛЕКОМУНІКАЦІЙНИХ СИСТЕМАХ. ЧАСТИНА 2. ДОСЛІДЖЕННЯ ТА МОДЕЛЮВАННЯ ПЕРЕДАВАННЯ ТЕЛЕВІЗІЙНИХ СИГНАЛІВ СТАНДАРТУ DVB-C І ІМПУЛЬСНОГО НАДШИРОКОСМУГОВОГО СИГНАЛУ РАДІОЛІНІЄЮ ТЕРАГЕРЦОВОГО ДІАПАЗОНУ

The laboratory testbed of a digital simplex radio-relay system of the terahertz range has been studied for the first time in practical terms. It consists of the receiver and transmitter parts of 130÷134 GHz frequency range and a digital modem with a channel data transmission of up to 1200 Mbps for a communication point-to-point distance under normal conditions within 1 km. It is shown that the proposed telecommunication system, which implements the concept of the creation of software-defined radio systems based on Wi-Fi technology, can be highly productive in the next generation mobile communication networks providing the appropriate transmission speeds, reliability, and security. It is studied the parameters of multichannel digital TV signal DVB-C standard when it is transmitted through the testbed of the transmitter and receiver parts of 130 GHz band. The results of the research showed that the application of lower part of terahertz frequency band (130 GHz) with a bandwidth of 24 MHz allows the transmission of three DVB-C television broadcasting channels with a total transport speed of 125 Mbit/s with a high subjective quality of TV programs. The results of the simulation of impulse ultrawideband (IR-UWB) signal transmission by the wireless link of terahertz band are presented. The results of researches of changes of IR-UWB Gaussian monocycle in the transmitter part and its reception by the receiver part of 130.4÷131.5 GHz terahertz band are presented for the first time. On the basis of the results of the research, the requirements for parameters of terahertz wireless link are formulated to ensure acceptable quality of ultrawideband impulse signals receiving. Development of the transmitter and receiver parts of radio relay system of the terahertz range has no direct current analogs in Ukraine. It can provide a significant breakthrough in the development of the telecommunications industry. The obtained research results will also contribute to the development of telecommunications-related industries, in particular: radio astronomy, inter-satellite communication, radar systems, medicine, etc.

The Method of Energy-Efficiency Investigations of the Newly Produced Marine Fuels Through an Application of the Laboratory Diesel Engine

Abstract The article deals with one of the scientific issue solved within frames of the research project financed by Voivodeship Fund for Environmental Protection and Water Management in Gdansk, namely, in particular, the method of energy investigations of the self-ignition engine in conditions of its supply with a non-standard (modified) marine fuel. The representative results of engine tests worked out on the especially built laboratory test bed have been presented. They aimed to elaborate energy profiles of a single-cylinder four-stroke Diesel engine in the form of Sankey diagrams of energy flows representing the most efficient and effective manner for the verification of a different kind of the modified marine fuels introduced on market. It is expected that the final results of the project will be interesting for their producers as well as the ship-owners of the operated ships, and also for the offices of sea administration as well as the inspectorates of environment protection.

Effectiveness of BPSK Modulation With Peak Noise Avoidance Algorithm in Smart Street Lighting Communications Based on PLC

Abstract This work reports the measurement results of long-terms tests obtained in real smart street lighting LV networks and in lab test bed. The measurements results are presented in the form of PER vs. SNR characteristics for BPSK coded and BPSK coded with peak noise avoidance algorithm. The surprising results obtained from real LV networks prompted the Authors to carry out detailed lab tests. The setup for lab tests is also presented in this work. To carry out lab tests a suitable software was prepared, it allowed to obtain results in 72 times shorter time comparing to real conditions; it is why this work can present characteristics of PER vs. SNR even for the values of PER at the level of 10−9. The work concludes with disadvantages of using the peak noise avoidance algorithm in PLC communication for smart street lighting.

Estimating Deformations of Laboratory Structures Subjected to Loadings Using Images Collected with Phone Camerase

A Fundamental civil engineering knowledge is the ability to understand, explain and calculate deformations of/in civil structures. New civil engineers acquire this knowledge at universities in material science, engineering mechanics and introduction to structural engineering modules. Structural deformations can be calculated when knowing material properties, geometry and boundary conditions of a structure and loads that are applied on/to it. Inverse engineering can be employed if deformations of a structure are known, but some other parameters are not known. Theoretical formulae are then tested using laboratory test beds, usually beams. Laboratory technicians are responsible for the acquisition of deformation measurements of laboratory tests. Their time is often limited and so is the number of available measurement collection devices such as dial gauges and strain gauges. If devices that do not log measured deformations are employed, information of structural deformations or response might be lost or readings might not be collected at required intervals. However, all laboratories do not offer luxury of sensors that are available at hand and technicians, which would have time to install sensors and collect data when needed, especially if this has to be done within a short period of notice. This paper introduces a low-cost vision-based system for deformation estimations of laboratory structures.

A Generalized Extended State Observer for Supercapacitor State of Energy Estimation With Online Identified Model

The state of energy (SoE) is a critical indicator for energy management in supercapacitor (SC) energy storage systems. The estimation accuracy of the SoE relies on the model fidelity, which means that the model parameters are required to be identified online to mitigate the aging effect. However, since the SC model is naturally nonlinear and high dimensional, it is typically difficult to identify the model parameters online. To address this issue, in this paper, we propose a generalized extended state observer (GESO) for SC SoE estimation based on an online identified model. A nonlinear mathematical model for SC is established based on the three branch equivalent circuit models, where the model parameters are online estimated with a designed modified recursive least square. A GESO is designed to estimate the SoE of SC in real time. A laboratory test bed has been built to verify the effectiveness of the proposed method. The experiment results show that the proposed method provides a better SoE estimation accuracy than the existing methods.

The concept of research on ecological, energy and reliability effects of modified marine fuel oils application to supply compression-ignition engines in real conditions

Within the article, basic assumptions of the research project financed by Regional Fund for Environmental Protection and Water in Gdansk were described. The project concerns the experimental investigations carried out on laboratory compression-ignition engine in conditions of its supply with a non-standard marine fuel oil. Configuration and measuring capability of laboratory test bed presently being constructed were introduced. The concept of engine tests implementation as well as a general outline of research methodology was characterised. After being accepted by Polish Committee for Stardarization they could become an effective and efficient verification tool for various types of modified fuel oils introduced on the market, both for the maritime administration officies and shipyards as well as ship owners in operation.

Opto-Dielectrometric Sensor for Measuring Total Incombustible Content in Underground Coal Mines

Coal dust produced during underground coal-mining, i.e., float dust, which deposits throughout the coal mine, can be feedstock for coal dust explosions. To prevent these explosions, inert rock dust (limestone dust) is applied to roof, floor, and rib areas of a coal mine. The ratio of incombustible mass (rock dust + incombustible content of coal dust) divided by total mass of the deposited dust is defined as the total incombustible content (TIC) of the deposited dust within the mine. Regulations require that a minimum TIC ratio (80%) to be maintained for safe working conditions inside the mine. This paper presents design, fabrication, and experimental results for a real-time sensing module, which uses continuous optical and dielectrometry methods to measure the TIC of the deposited float dust/rock dust. The optical sensor determines the TIC of the deposited dust based on optical reflection, which is described by modified Beer Law. We present an extension of the Bouguer-Beer–Lambert Law to find the relation between the reflectivity of a layer of known thickness (obtained by interdigital dielectrometry sensor) of a dust mixture to the ratio of each constituent. We also present the experimental results from testing the sensor prototypes in a realistic laboratory test bed that is subjected to the deposition of the coal dust/rock dust mixture. The sensor performance and stability at different humidity levels is evaluated and the accuracy of the results is compared with the currently established best practices for measuring TIC in underground coal mines.

CCR: Cost‐aware cell relocation in 6TiSCH networks

AbstractThe Internet Engineering Task Force 6TiSCH Working Group standardizes the protocol stack for the Industrial Internet of Things, which combines the industrial performance of IEEE802.15.4 time‐slotted channel hopping (TSCH) with the addressability and Internet integration capabilities of Internet Protocol version 6. The 6top Protocol, which is part of 6TiSCH, allows distributed management of the TSCH communication schedule. The Scheduling Function Zero (SF0) is the default algorithm for a node to decide when to add/remove cells to its neighbors. SF0 picks the cells to add randomly; hence, it is possible that 2 nearby pairs of nodes pick the same cell, resulting in a schedule collision. This article introduces cost‐aware cell relocation (CCR), which is a solution to detect and fix such schedule collisions in a distributed manner. CCR monitors the performance of individual cells and uses that information to detect collisions. When such a collision is detected on a cell, neighbor nodes communicate to relocate that cell to a different slot/channel in the TSCH schedule. We implement CCR and run it on a 5‐node network on the Internet of Things Laboratory testbed. The results show that, compared with today's SF0 and for the same traffic requirements, CCR increases the average packet delivery ratio by 2% and reduces the number of cells that need to be scheduled by 27.3%.

Experiments and simulation of a net closing mechanism for tether-net capture of space debris

This research addresses the design and testing of a debris containment system for use in a tether-net approach to space debris removal. The tether-net active debris removal involves the ejection of a net from a spacecraft by applying impulses to masses on the net, subsequent expansion of the net, the envelopment and capture of the debris target, and the de-orbiting of the debris via a tether to the chaser spacecraft. To ensure a debris removal mission's success, it is important that the debris be successfully captured and then, secured within the net. To this end, we present a concept for a net closing mechanism, which we believe will permit consistently successful debris capture via a simple and unobtrusive design. This net closing system functions by extending the main tether connecting the chaser spacecraft and the net vertex to the perimeter and around the perimeter of the net, allowing the tether to actuate closure of the net in a manner similar to a cinch cord. A particular embodiment of the design in a laboratory test-bed is described: the test-bed itself is comprised of a scaled-down tether-net, a supporting frame and a mock-up debris. Experiments conducted with the facility demonstrate the practicality of the net closing system. A model of the net closure concept has been integrated into the previously developed dynamics simulator of the chaser/tether-net/debris system. Simulations under tether tensioning conditions demonstrate the effectiveness of the closure concept for debris containment, in the gravity-free environment of space, for a realistic debris target. The on-ground experimental test-bed is also used to showcase its utility for validating the dynamics simulation of the net deployment, and a full-scale automated setup would make possible a range of validation studies of other aspects of a tether-net debris capture mission.

The Harmonic Order Tracking Analysis (HOTA) for the Diagnosis of Induction Generators Working Under Steady State Regime

Improved fault diagnostic techniques in induction generators is a field of growing interest given the negative impact *that unexpected breakdowns have on energy production and on the electrical system. New diagnostic techniques based on induction generator currents monitoring have recently been developed, but their use is still irrelevant despite the advantages that presents to detect electrical faults in the generator. This situation is due to the needs of high computing power and memory resources which are not available in embedded devices for on-line monitoring, also, to the use of signal processing techniques that generate volumes of data difficult to transfer to control centres, where they could be processed. This paper proposes the use of a recent methodology known as the harmonic order tracking analysis (HOTA) that solve these problems to for the diagnosis of induction generators. This approach can be implemented in low cost digital devices; the resultant patterns are very simple and easily interpretable, even by nonqualified personnel. Moreover, these patterns are characterized by a very low number of parameters, which make easy their transmission to remote control centres. In this paper the practical application of this approach is proposed using a laboratory test bed.

Laboratory test bed for sonic boom propagation

Varying ethanol concentration with depth, Hobaek et al. [AIP Proc. 838, 2006)] simulated the atmospheric sound speed profile scaled in a water tank and mimicked sonic boom propagation. Some limitations of their groundbreaking design included complexity, fragility, size, safety, one-dimensionality, tonal bursts instead of impulsive shocks, and the inability to scale density, absorption, turbulence, or other nonlinearities. Recognizing the time and cost savings of scaled overflight experiments in a laboratory environment, this work is meant to address certain limitations and investigate the Mach cut-off phenomena. Our primary advances are to use gel layers instead of fluid mixtures and lithotripter shock pulses. We defocused and modified a Dornier Compact S lithotripter to vary source angle in a 500-liter polycarbonate tank, measured shocks with a fiber optic hydrophone, and developed fluid-like gels with negligible shear-wave generation and robustness against cavitation. The sound speed, attenuation, inhomogeneity, and nonlinearity are adjustable within each gel layer. The result is a more flexible, controllable, and durable atmospheric analogue. [Work supported by the FAA. The opinions, findings, conclusions, and recommendations expressed in this material are those of the authors and do not necessarily reflect the views of ASCENT FAA Center of Excellence sponsor organizations.]

The Two-Step P2P Simulation Approach

In this article a framework is introduced that can be used to analyse the effects & requirements of P2P applications onapplication and on network layer. P2P applications are complex and deployed on a large scale, pure packet level simulations do not scale well enough to analyse P2P applications in a large network with thousands of peers. It is also difficult to assess the effect of application level behavior on the communication system. We therefore propose an approach starting with a more abstract and therefore scalable application level simulation. For the application layer a specific simulation framework wasdeveloped. The results of the application layer simulations plus some estimated background traffic are fed into a packet layer simulator like NS2 (or our lab testbed) in a second step to perform some detailed packet layer analysis such as loss and delay measurements. This can be done for a subnetwork of the original network to avoid scalability problems.

Modeling the internet of things: a hybrid modeling approach using complex networks and agent-based models

Sensors, coupled with transceivers, have quickly evolved from technologies purely confined to laboratory test beds to workable solutions used across the globe. These mobile and connected devices form the nuts and bolts required to fulfill the vision of the so-called internet of things (IoT). This idea has evolved as a result of proliferation of electronic gadgets fitted with sensors and often being uniquely identifiable (possible with technological solutions such as the use of Radio Frequency Identifiers). While there is a growing need for comprehensive modeling paradigms as well as example case studies for the IoT, currently there is no standard methodology available for modeling such real-world complex IoT-based scenarios. Here, using a combination of complex networks-based and agent-based modeling approaches, ​we present a novel approach to modeling the IoT. Specifically, the proposed approach uses the Cognitive Agent-Based Computing (CABC) framework to simulate complex IoT networks. We demonstrate modeling of several standard complex network topologies such as lattice, random, small-world, and scale-free networks. To further demonstrate the effectiveness of the proposed approach, we also present a case study and a novel algorithm for autonomous monitoring of power consumption in networked IoT devices. We also discuss and compare the presented approach with previous approaches to modeling. Extensive simulation experiments using several network configurations demonstrate the effectiveness and viability of the proposed approach.

Mixed-reality learning environments: Integrating mobile interfaces with laboratory test-beds

Even as mobile devices have become increasingly powerful and popular among learners and instructors alike, research involving their comprehensive integration into educational laboratory activities remains largely unexplored. This paper discusses efforts to integrate vision-based measurement and control, augmented reality (AR), and multi-touch interaction on mobile devices in the development of Mixed-Reality Learning Environments (MRLE) that enhance interactions with laboratory test-beds for science and engineering education. A learner points her device at a laboratory test-bed fitted with visual markers while a mobile application supplies a live view of the experiment augmented with interactive media that aid in the visualization of concepts and promote learner engagement. As the learner manipulates the augmented media, her gestures are mapped to commands that alter the behavior of the test-bed on the fly. Running in the background of the mobile application are algorithms performing vision-based estimation and wireless control of the test-bed. In this way, the sensing, storage, computation, and communication (SSCC) capabilities of mobile devices are leveraged to relieve the need for laboratory-grade equipment, improving the cost-effectiveness and portability of platforms to conduct hands-on laboratories. We hypothesize that students using the MRLE platform demonstrate improvement in their knowledge of dynamic systems and control concepts and have generally favorable experiences using the platform. To validate the hypotheses concerning the educational effectiveness and user experience of the MRLEs, an evaluation was conducted with two classes of undergraduate students using an illustrative platform incorporating a tablet computer and motor test-bed to teach concepts of dynamic systems and control. Results of the evaluation validate the hypotheses. The benefits and drawbacks of the MRLEs observed throughout the study are discussed with respect to the traditional hands-on, virtual, and remote laboratory formats.

Technology of Ultrasonic Treatment of High-Viscosity Oil from Yarega Oilfield to Improve the Rheological Properties of Oil

The article investigates the possibility of applying ultrasonic treatment oil from Yarega oilfield to improve of rheological properties, reduce oil viscosity in Russian pipeline transportation system, and increase its efficiency and performance. Created laboratory test bed of ultrasonic waves.

Mounted Smartphones as Measurement and Control Platforms for Motor-Based Laboratory Test-Beds.

Laboratory education in science and engineering often entails the use of test-beds equipped with costly peripherals for sensing, acquisition, storage, processing, and control of physical behavior. However, costly peripherals are no longer necessary to obtain precise measurements and achieve stable feedback control of test-beds. With smartphones performing diverse sensing and processing tasks, this study examines the feasibility of mounting smartphones directly to test-beds to exploit their embedded hardware and software in the measurement and control of the test-beds. This approach is a first step towards replacing laboratory-grade peripherals with more compact and affordable smartphone-based platforms, whose interactive user interfaces can engender wider participation and engagement from learners. Demonstrative cases are presented in which the sensing, computation, control, and user interaction with three motor-based test-beds are handled by a mounted smartphone. Results of experiments and simulations are used to validate the feasibility of mounted smartphones as measurement and feedback control platforms for motor-based laboratory test-beds, report the measurement precision and closed-loop performance achieved with such platforms, and address challenges in the development of platforms to maintain system stability.

The Effects of Air Flow Rates, Secondary Air Inlet Geometry, Fuel Type, and Operating Mode on the Performance of Gasifier Cookstoves.

Development of biomass cookstoves that reduce emissions of CO and PM2.5 by more than 50% and 95%, respectively, compared to a three-stone fire has been promoted as part of efforts to reduce exposure to household air pollution (HAP) among people that cook with solid fuels. Gasifier cookstoves have attracted interest because some have been shown to emit less CO and PM2.5 than other designs. A laboratory test bed and new test procedure were used to investigate the influence of air flow rates, stove geometry, fuel type, and operating mode on gasifier cookstove performance. Power output, CO emissions, PM2.5 emissions, fuel consumption rates, producer gas composition, and fuel bed temperatures were measured. The test bed emitted <41 mg·MJd–1 PM2.5 and <8 g·MJd–1 CO when operating normally with certain prepared fuels, but order of magnitude increases in emission factors were observed for other fuels and during refueling. Changes in operating mode and fuel type also affected the composition of the producer gas entering the secondary combustion zone. Overall, the results suggest that the effects of fuel type and operator behavior on emissions need to be considered, in addition to cookstove design, as part of efforts to reduce exposure to HAP.