Critical System Components Research Articles

A New Multiattribute Decision Making Support Tool for Identifying Critical Components in Power Transmission Systems

The present context of the electric industry, characterized by competitive markets, privatization, and regulatory of technical requirements forces the power utilities to optimize their asset management practices and develop the requisite decision plans techno-economically. Practically approaching, this paper devises a new support tool based on a multiattribute decision making (MADM) framework in combination with analytical hierarchical process (AHP) to determine the most critical components of power transmission systems. Measure of system-wide reliability performance, outage cost, marginal clearing prices demonstrative of market fairness, and network losses are among the attributes considered in this paper for component criticality assessment. With the frequent existence of qualitative and quantitative attributes, the proposed approach can effectively help to deal with the existent uncertainty and conventional judgment vagueness. As verified in a case study on the IEEE Reliability Test System (IEEE-RTS), the proposed framework introduces its applicability and efficiency for the practical asset management optimizations in electric utilities.

Interaction of MreB-derived antimicrobial peptides with membranes

Antimicrobial peptides are critical components of defense systems in living forms. The activity is conferred largely by the selective membrane-permeabilizing ability. In our earlier work, we derived potent antimicrobial peptides from the 9-residue long, N-terminal amphipathic helix of E. coli MreB protein. The peptides display broad-spectrum activity, killing not only Gram-positive and Gram-negative bacteria but opportunistic fungus, Candida albicans as well. These results proved that membrane-binding stretches of bacterial proteins could turn out to be self-harming when applied from outside. Here, we studied the membrane-binding and membrane-perturbing potential of these peptides. Steady-state tryptophan fluorescence studies with tryptophan extended peptides, WMreB1-9 and its N-terminal acetylated analog, Ac-WMreB1-9 show preferential binding to negatively-charged liposomes. Both the peptides cause permeabilization of E. coli inner and outer-membranes. Tryptophan-lacking peptides, though permeabilize the outer-membrane efficiently, little permeabilization of the inner-membrane is observed. These data attest membrane-destabilization as the mechanism of rapid bacterial killing. This study is expected to motivate the research in identifying microbes' self-sequences to combat them.

Sea Dyke Rehabilitation and Climate Change in Dutch and Japanese Contexts

The purpose of this paper is to analyze the relationship between climate change and the need to rehabilitate sea dykes. Sea dykes are a critical component of coastal infrastructure and national flood prevention systems and are increasingly susceptible to a number of failure mechanisms under climate change conditions. This paper will explore case studies of sea dyke rehabilitation and climate change in both the Netherlands and Japan. Both countries have urban areas within close proximity to coastal areas and have constructed sea and river dykes as part of their national flood prevention plans. The International Panel on Climate Change published a report in February 2012 stating that mean global temperatures are going to increase by 1 to 3 degrees Celcius by 2050, which will affect global weather conditions. The characteristics of climate change which most affect sea dykes include the frequency and severity of storms as well as global sea level rise. These trends increase the risk of dyke failure modes such as overtopping, micro instability, and erosion of non-reinforced inner slopes. Techniques for rehabilitation both proven and proposed will be discussed with a particular focus on methods for implementation as well as the policy framework of these projects.

Reducing Risk for Emotional and Behavioral Disorders in Late Elementary School: A Comparison of Two Targeted Interventions

Students with elevated levels of risk require targeted Tier 2 behavioral interventions that are efficient and effective to prevent the need for more intensive, special education supports. Although Tier 2 is a critical component of multi-tiered systems of support, a paucity of research exists regarding how best to provide evidence-based Tier 2 interventions, particularly for students with comorbid deficit areas. The current trial involved 33 third- through fifth-grade participants who were assigned to one of three study groups: (a) control, (b) check-in/check-out, or (c) Coping Power. The Behavior Assessment of Children in Schools–2 (BASC-2) was used to measure changes in externalizing behavior, along with its three component subscales. The Strengths and Difficulties Questionnaire (SDQ) was used to examine change in broad emotional and behavioral risk profiles. Teachers rated participants on the SDQ and BASC-2 at preintervention, postintervention, and follow-up. Results indicate that both check-in/check-out and Coping Power yielded decreases in externalizing behavior, with Coping Power also resulting in significant decreases in overall emotional and behavioral risk. A discussion of these results along with implications for future research and study limitations are presented.

The Role of Microsystems Integration Towards Point-of-Care Clozapine Treatment Monitoring in Schizophrenia.

We present a perspective on microsystems integration aspects for concurrent cellular and molecular sensing in a lab-on-a-chip device. While of interest for a range of applications, very few - narrowly focused - examples of such devices can be found in the literature. Here, we approach the challenge from a systems level, considering sensor integration both in parallel and in series. Our study is specifically geared toward schizophrenia treatment, where concurrent blood monitoring of the antipsychotic clozapine and white blood cells could lead to improved treatment outcomes. We evaluate the critical system components for either design, namely plasma skimming (parallel) and in-blood clozapine detection (series). We find that plasma skimming is infeasible, but for the first time demonstrate direct detection of clozapine in whole blood. With a corresponding series-integrated microsystem, we finally demonstrate downstream white blood cell analysis on the same samples using impedance cytometry. We thus present the first lab-on-a-chip device capable of label- and reagent-free concurrent sensing of cellular and molecular markers.

Developing the methodology of colour gamut analysis and print quality evaluation for textile ink‐jet printing: Delphi method

This research used the Delphi method to investigate current colour gamut analysis methods, which is a critical component of colour management systems (CMS). Thirteen ink‐jet printing experts were interviewed to understand how they manage colour and their process for analysing and comparing colour gamut. A significant result of this study was the development of a four‐stage process model for colour gamut analysis and print quality evaluation for textile ink‐jet printing. The optimal process model was verified and approved by experts. This study uncovered an industry initiative toward the improvement of CMS for more accurate colour matching, a need to stabilise variables in the manufacturing process, and a need to standardise related tests and evaluations. The study also revealed new CMS software and technologies developed for ink formulation and pre‐/post‐treatment methods to facilitate high quality production in textile ink‐jet printing.

User-Centric Networking for Dense C-RANs: High-SNR Capacity Analysis and Antenna Selection

Ultra-dense cloud radio access networks (C-RANs) are an example of the architectures that will be critical components of the next-generation wireless systems. In a C-RAN architecture, an amorphous cellular framework, where each user connects to a few nearby remote radio heads (RRHs) to form its own cell, appears to be promising. In this paper, we study the ergodic capacity of such amorphous cellular networks at high signal-to-noise ratios (SNRs) where we model the distribution of the RRHs by a Poisson point process. We derive tractable approximations of the ergodic capacity at high-SNRs for arbitrary antenna configurations, and tight lower bounds for the ergodic capacity when the numbers of antennas are the same at both ends of the link. In contrast to prior works on distributed antenna systems, our results are derived based on random matrix theory and involve only standard functions which can be much more easier evaluated. The impact of the system parameters on the ergodic capacity is investigated. By leveraging our analytical results, we propose two efficient scheduling algorithms for RRH selection for energy-efficient transmission. Our algorithms offer a substantial improvement in energy efficiency compared with the strategy of connecting a fixed number of RRHs to each user.

Dual-Polarized Antenna Arrays with CMOS Power Amplifiers for SiP Integration at W-Band

Abstract This paper presents requirements and front-end solutions for low-cost communication systems with data rates of 100 Gbit/s. Link budget analyses in different mass-market applications are conducted for that purpose. It proposes an implementation of the front-end as an active antenna array with support for beam steering and polarization multiplexing over the full W-band. The critical system components are investigated and presented. This applies to a transformer coupled power amplifier (PA) in 40 nm bulk CMOS. It shows saturated output power of more than 10 dBm and power-added-efficiency of more than 10 % over the full W-band. Furthermore, the performance of microstrip-to-waveguide transitions is shown exemplarily as an important part of the active antenna as it interfaces active circuitry and antenna in a polymer-and-metal process. The transition test design shows less than 0.9 dB insertion loss and more than 12 dB return loss for the differential transition over the full W-band.

Acoustic Call Library and Detection Distances for Bats of Swaziland

Bats are a critical component of most terrestrial systems, yet accurately assessing species richness and abundances remains a challenge. The use of acoustic monitoring has increasingly been used to assess bat communities. Compared with more traditional trapping surveys, acoustic monitoring is relatively easy to use and vastly increases the amount of data collected. However, the ability to accurately identify bat calls from acoustic detectors is limited by the availability of regional call libraries describing the calls of local species. Further, the lack of knowledge of detection distances for different species limits the ability to compare activity levels or abundances between species. We developed an echolocation call library based on zero-crossing recordings with Anabat Express detectors that can be applied broadly to bat acoustic detector surveys across the savanna systems of Swaziland and South Africa, and potentially the broader region of Southern Africa. We also compared detection distances for dif...

The ACE2/Angiotensin-(1-7)/Mas Receptor Axis: Pleiotropic Roles in Cancer.

Cancer remains one of the most common causes of death and disability and represents a major economic burden in industrialized nations. The renin-angiotensin system (RAS) has been well-recognized as one of the most important regulators of both normal and pathological physiological processes in the brain, kidney, heart, and blood vessels. The activation of the angiotensin-converting enzyme 2/angiotensin-(1–7)/mitochondrial assembly receptor [ACE2/Ang-(1–7)/MasR] axis, which is one component of the RAS, has recently been identified as a critical component of pulmonary systems, gastric mucosa, and cancer. However, the ability of the ACE2/Ang-(1–7)/MasR axis to suppress or promote cancer has not been fully elucidated. In this review, we focus on recent experimental and clinical studies investigating the basic properties, roles, and mechanisms of ACE2, Ang-(1–7), and the MasR, as well as the axis pathway, to provide insights into possible therapeutic strategies for treating cancer that target the ACE2/Ang-(1–7)/MasR axis.

Role of Human Factors Engineering in Infection Prevention: Gaps and Opportunities.

Opinion statementHuman factors engineering (HFE), with its focus on studying how humans interact with systems, including their physical and organizational environment, the tools and technologies they use, and the tasks they perform, provides principles, tools, and techniques for systematically identifying important factors, for analyzing and evaluating how these factors interact to increase or decrease the risk of Healthcare-associated infections (HAI), and for identifying and implementing effective preventive measures. We reviewed the literature on HFE and infection prevention and control and identified major themes to document how researchers and infection prevention staff have used HFE methods to prevent HAIs and to identify gaps in our knowledge about the role of HFE in HAI prevention and control. Our literature review found that most studies in the healthcare domain explicitly applying (HFE) principles and methods addressed patient safety issues not infection prevention and control issues. In addition, most investigators who applied human factors principles and methods to infection prevention issues assessed only one human factors element such as training, technology evaluations, or physical environment design. The most significant gap pertains to the limited use and application of formal HFE tools and methods. Every infection prevention study need not assess all components in a system, but investigators must assess the interaction of critical system components if they want to address latent and deep-rooted human factors problems.

A Statistical Framework for Improved Automatic Flaw Detection in Nondestructive Evaluation Images

ABSTRACTNondestructive evaluation (NDE) techniques are widely used to detect flaws in critical components of systems like aircraft engines, nuclear power plants, and oil pipelines to prevent catastrophic events. Many modern NDE systems generate image data. In some applications, an experienced inspector performs the tedious task of visually examining every image to provide accurate conclusions about the existence of flaws. This approach is labor-intensive and can cause misses due to operator ennui. Automated evaluation methods seek to eliminate human-factors variability and improve throughput. Simple methods based on peak amplitude in an image are sometimes employed and a trained-operator-controlled refinement that uses a dynamic threshold based on signal-to-noise ratio (SNR) has also been implemented. We develop an automated and optimized detection procedure that mimics these operations. The primary goal of our methodology is to reduce the number of images requiring expert visual evaluation by filtering out images that are overwhelmingly definitive on the existence or absence of a flaw. We use an appropriate model for the observed values of the SNR-detection criterion to estimate the probability of detection. Our methodology outperforms current methods in terms of its ability to detect flaws. Supplementary materials for this article are available online.

Automated policy generation for testing access control software

ABSTRACTAccess control systems (ACS) are a critical component of modern information technology systems and require rigorous testing. If the ACS has defects, then the deployment is not secure and is a threat to system security. Firewalls are an important example of an ACS, and formally verifying firewall systems has recently attracted attention. We present an automated software-testing tool, PG, for the production of firewall policies for use in firewall policy enforcement testing. PG utilizes a number of heuristic techniques to improve space coverage over traditional systems based on randomly generated firewall policies. An empirical study is presented demonstrating that PG generates firewall policies with superior coverage compared to traditional policy-generation techniques. The extension of PG beyond firewall systems to other ACS situations is outlined.

External quality assessment in resource-limited countries.

IntroductionHealth laboratory services are a critical component of national health systems but face major operational challenges in resource-limited (RL) settings. New funding for health systems strengthening in RL countries has increased the demand for diagnostics and provided opportunities to address these constraints. An approach to sustainably strengthen national laboratory systems in sub-Saharan African countries is the Strengthening Laboratory Management Toward Accreditation (SLMTA) programme. External Quality Assessment (EQA) is a requirement for laboratory accreditation. EQA comprises proficiency testing (PT), rechecking of samples and on-site evaluation.Materials and methodsA systematic literature search was conducted to identify studies addressing laboratory EQA and quality monitoring in RL countries. Unpublished reports were also sought from national laboratory authorities and personnel.ResultsPT schemes in RL countries are provided by commercial companies, institutions in developed countries and national programmes. Most government-supported PT schemes address single diseases using a vertical approach. Regional approaches to delivering PT have also been implemented across RL countries. Rechecking schemes address mainly tuberculosis (TB), malaria and human immunodeficiency virus (HIV); integrated rechecking programmes have been piloted. Constraints include sample transportation, communication of results, unknown proficiency of referee staff and limited resources for corrective action. Global competency assessment standards for malaria microscopists have been established.ConclusionsEQA is vital for monitoring laboratory performance and maintaining quality of laboratory services, and is a valuable tool for identifying and assessing technology in use, identifying gaps in laboratory performance and targeting training needs. Accreditation of PT providers and competency of EQA personnel must be ensured.

A Review of Li-ion Battery Equivalent Circuit Models

Batteries are critical components of electric vehicles and energy storage systems. The connection of a battery to the power grid for charge and discharge greatly affects energy storage. Therefore, an accurate and easy-to-observe battery model should be established to achieve systematic design, simulation, and SOC (state of charge) estimations. In this review, several equivalent circuit models of representative significance are explained, and their respective advantages and disadvantages are compared to determine and outline their reasonable applications to Li-ion batteries. Numerous commonly used model parameter identification principles are summarized as well, and basic model verification methods are briefly introduced for the convenient use of such models.

2B-Alert Web: An Open-Access Tool for Predicting the Effects of Sleep/Wake Schedules and Caffeine Consumption on Neurobehavioral Performance.

Computational tools that predict the effects of daily sleep/wake amounts on neurobehavioral performance are critical components of fatigue management systems, allowing for the identification of periods during which individuals are at increased risk for performance errors. However, none of the existing computational tools is publicly available, and the commercially available tools do not account for the beneficial effects of caffeine on performance, limiting their practical utility. Here, we introduce 2B-Alert Web, an open-access tool for predicting neurobehavioral performance, which accounts for the effects of sleep/wake schedules, time of day, and caffeine consumption, while incorporating the latest scientific findings in sleep restriction, sleep extension, and recovery sleep. We combined our validated Unified Model of Performance and our validated caffeine model to form a single, integrated modeling framework instantiated as a Web-enabled tool. 2B-Alert Web allows users to input daily sleep/wake schedules and caffeine consumption (dosage and time) to obtain group-average predictions of neurobehavioral performance based on psychomotor vigilance tasks. 2B-Alert Web is accessible at: https://2b-alert-web.bhsai.org. The 2B-Alert Web tool allows users to obtain predictions for mean response time, mean reciprocal response time, and number of lapses. The graphing tool allows for simultaneous display of up to seven different sleep/wake and caffeine schedules. The schedules and corresponding predicted outputs can be saved as a Microsoft Excel file; the corresponding plots can be saved as an image file. The schedules and predictions are erased when the user logs off, thereby maintaining privacy and confidentiality. The publicly accessible 2B-Alert Web tool is available for operators, schedulers, and neurobehavioral scientists as well as the general public to determine the impact of any given sleep/wake schedule, caffeine consumption, and time of day on performance of a group of individuals. This evidence-based tool can be used as a decision aid to design effective work schedules, guide the design of future sleep restriction and caffeine studies, and increase public awareness of the effects of sleep amounts, time of day, and caffeine on alertness.

Comparison and evaluation of railway subgrade quality detection methods

Subgrade is a critical component of railway systems since it provides a stable platform for the track substructure. The implementation of quality assurance methods is very important during the construction of a new railway subgrade and in monitoring the working performance of operating railways. There are several indicators available to measure the compaction and mechanical performance of a completed subgrade system, including compaction degree ( K), porosity ( n), modulus of subgrade reaction ( K30), basic bearing capacity ([Formula: see text]), strain moduli ( Ev), dynamic modulus of deformation ( Evd), and light dynamic penetration ( N10). The objective of this research was to compare and evaluate the frequently used engineering methods in order to select the important and reliable indicators of field parameters. Four soil models with different degree of compaction were considered in the common laboratory tests and detection methods in China to determine the construction quality. The implementation and test results of these methods were analyzed and compared. The study results indicate that K correlates with n linearly. There is also a good correlation among K30, Ev, and Evd. As a recommendation, K is considered as the controlling indicator for compaction performance, and Ev2 and Evd are considered as the controlling indicators for railway subgrade stiffness evaluation. The bearing capacity or strength indicators may be added to the quality detection work in heavy-haul railway construction.

Research on aging evaluation and remaining lifespan prediction of composite insulators in high temperature and humidity regions

Composite insulators are the critical components of power transmission systems. 371 composite insulators with an operating duration between 3 and 22 years from the lines in high temperature and humidity regions were sampled. The material properties, mechanical properties, electrical properties and interface properties of these insulators were researched systematically. Moreover, 19 aging characteristic index were put forward to describe the aging conditions of insulators. We analyzed the correlation between the aging index and operating years, and corresponding aging mechanism was discussed in this paper. Meanwhile, according to the analysis results, we established lifespan prediction models based on physics and statistics respectively. The results showed: lifespan of the sampled insulators was determined by the thermal oxidation process of silicone rubber. Lifespan of the silicone rubber material was 14.6 years while the electrical lifespan of composite insulator was 18.9 years. With regard to the rest of the insulators in high-temperature and high-humidity regions, their remaining lifespan could be predicted in accordance with the mechanical load and Fourier translation infrared spectroscopy (FTIR) test results. In the end, we selected 20 insulators which had run for 14 years, and predicted their lifespan with the method mentioned in this article, the forecast error was 1 year.

Elemental characterisation of melanin in feathers via synchrotron X-ray imaging and absorption spectroscopy.

Melanin is a critical component of biological systems, but the exact chemistry of melanin is still imprecisely known. This is partly due to melanin’s complex heterogeneous nature and partly because many studies use synthetic analogues and/or pigments extracted from their natural biological setting, which may display important differences from endogenous pigments. Here we demonstrate how synchrotron X-ray analyses can non-destructively characterise the elements associated with melanin pigment in situ within extant feathers. Elemental imaging shows that the distributions of Ca, Cu and Zn are almost exclusively controlled by melanin pigment distribution. X-ray absorption spectroscopy demonstrates that the atomic coordination of zinc and sulfur is different within eumelanised regions compared to pheomelanised regions. This not only impacts our fundamental understanding of pigmentation in extant organisms but also provides a significant contribution to the evidence-based colour palette available for reconstructing the appearance of fossil organisms.

System Hardening and Condition-Based Maintenance for Electric Power Infrastructure Under Hurricane Effects

The devastating impact of hurricanes on electric power systems calls for development of sophisticated asset management strategies for utility infrastructure. El Nino/La Nina are shown to have seasonal effects on hurricane arrivals in the long-term climatological horizon. The periodic effects of such natural phenomena need to be analyzed and incorporated into decision making processes for strategic asset management of power systems. In this paper, an integrated infrastructure hardening and condition-based maintenance scheduling model for critical components of the power systems is proposed. Partially observable Markov decision processes are used to formulate the problem. The survival function against hurricanes is derived as a dynamic stress–strength model, and is incorporated in the proposed framework. A generalized formulation for two hardening strategies, i.e., with temporary and permanent hardening effects, is proposed. Case studies are conducted to analyze the model and further illustrate the effectiveness of the proposed strategy.