Reliability Benefits Research Articles

On including travel time reliability of road traffic in appraisal

In many countries, decision-making on proposals for national or regional infrastructure projects in passenger and freight transport includes carrying out a cost–benefit analysis for these projects. Reductions in travel times are usually a key benefit. However, if a project also reduces the variability of travel time, travellers, freight operators and shippers will enjoy additional benefits, the ‘reliability benefits’. Until now, these benefits are usually not included in the cost–benefit analysis. To include reliability of travel or transport time in the cost–benefit analysis of infrastructure projects not only monetary values of reliability, but also reliability forecasting models are needed. As a result of an extensive feasibility study carried out for the German Federal Ministry of Transport, Building and Urban Development this paper aims to provide a literature overview and outcomes of an expert panel on how best to calculate and monetise reliability benefits, synthesised into recommendations for implementing travel time reliability into existing transport models in the short, medium, and long term. The paper focuses on road transport, which has also been the topic for most of the available literature on modelling and valuing transport time reliability.

Ridership Response to Incremental Bus Rapid Transit Upgrades in North America

This paper explores ridership increases in response to incrementally upgraded bus services in U.S. and Canadian cities. Current guidelines for developing bus rapid transit (BRT) corridors reveal a tension between comprehensive implementation of full-fledged corridors on the one hand and incremental, flexible development on the other. A review of the literature discusses this tension, various BRT elements, and the impact of these elements on performance and ridership. A methodology for comparing high-productivity bus corridors in different contexts using general transit feed specification (GTFS) data and a spatial database framework is described. Longitudinal and cross-sectional sketch models, with corridors as the unit of analysis, offer some insights into the relative impact of BRT features and external factors. Current data limitations allow for suggestive, if not definitive, results. Dedicated lanes and signal priority were positively correlated with increased ridership in some models tested, even when decreased travel time was controlled for and, suggesting that they may have had important perception and reliability benefits beyond improved speeds. While BRT can be a promising mode for a range of contexts, this analysis suggests that service frequency and reliability improvements are the common foundation for successful projects. Building political momentum for sustained improvements in bus networks is a challenge; the use of emerging data sources, such as GTFS, to compare incremental BRT projects allows for a better understanding of projects that can help meet this challenge.

The effect of action video game playing on sensorimotor learning: Evidence from a movement tracking task

Research on the impact of action video game playing has revealed performance advantages on a wide range of perceptual and cognitive tasks. It is not known, however, if playing such games confers similar advantages in sensorimotor learning. To address this issue, the present study used a manual motion-tracking task that allowed for a sensitive measure of both accuracy and improvement over time. When the target motion pattern was consistent over trials, gamers improved with a faster rate and eventually outperformed non-gamers. Performance between the two groups, however, did not differ initially. When the target motion was inconsistent, changing on every trial, results revealed no difference between gamers and non-gamers. Together, our findings suggest that video game playing confers no reliable benefit in sensorimotor control, but it does enhance sensorimotor learning, enabling superior performance in tasks with consistent and predictable structure.

Evaluation of Operational Reliability of a Microgrid Using a Short-Term Outage Model

Island-capable microgrids can potentially improve customer reliability, but protection-related issues can adversely affect this reliability benefit. At the same time, average annualized indices often do not effectively convey a complete picture of load-point reliabilities in microgrids integrated with multiple weather-dependent microsources. The primary goal of this work is to investigate the impacts of protection system and operating conditions on the reliability indices of a microgrid. The proposed method utilizes a short-term outage model that quantifies the relationship between state variables and the outage rate of component. A hybrid approach is proposed, which combines scenario selection and enumerative analysis. Simulations on a test system illustrate the dependence of operational reliability on factors such as local meteorological conditions, correlation between variable generation and loads, as well as the effects of protection system operations. Finally, some recommendations on the parameter settings of protection system are provided to enhance the system reliability.

DTC of B4-Inverter-Fed BLDC Motor Drives With Reduced Torque Ripple During Sector-to-Sector Commutations

The paper deals with the direct torque control (DTC) of brushless DC (BLDC) motor drives fed by four-switch inverters (also known as B4-inverters) rather than six-switch inverters (also known as B6-inverters) in conventional drives. The B4-inverter could be regarded as a reconfigured topology of the B6-inverter in case of a switch/leg failure which represents a crucial reliability benefit for many applications especially in electric and hybrid propulsion systems. The principle of operation of the BLDC motor is firstly recalled considering both cases of B6- and B4-inverters in the armature, with emphasis on the two- and three-phase conduction modes. Then, the DTC of B4-inverter-fed BLDC motor drives is treated considering three strategies, such as: 1) DTC-1: a strategy inspired from the one intended to B6-inverter-fed BLDC motor drives; 2) DTC-2: a strategy that considers a dedicated vector selection subtable in order to independently control the torques developed by the phases connected to the B4-inverter legs during their simultaneous conduction; and 3) DTC-3: a proposed strategy that eliminates the torque dips penalizing DTC-2 during sector-to-sector commutations. Following the design of the corresponding vector selection tables and subtables (if any), an experimentally based comparative study of the three DTC strategies is carried out considering, in the first step, the BLDC motor steady-state operation under DTC-1 and DTC-3. Then, the comparison is extended to the BLDC motor features during sector-to-sector commutations, under DTC-2 and DTC-3. The experimental results clearly validate the predicted performance of the proposed DTC strategy.

Sense of Humor, Stable Affect, and Psychological Well-Being

A good sense of humor has been implicated as a quality that could contribute to psychological well-being. The mechanisms through which sense of humor might operate include helping to reappraise threats, serving as a character strength, or facilitating happiness. The current research attempts to integrate these possibilities by examining whether a good sense of humor might operate globally by helping to maintain a more stable positive affect. Stable positive affect has been shown to facilitate more effective problem solving and to build resilience. However, not all humor is adaptive humor, so we also examine the roles that different styles of humor use might play. Individual differences in humor styles were used to predict stable levels of affect. Then, in a longitudinal design, humor styles and stable affect were used to predict subsequent resilience and psychological health. The results indicated that stable affect was related to resilience and psychological well-being, and that a sense of humor that involves self-enhancing humor, humor based on maintaining a humorous perspective about one’s experiences, was positively related to stable positive affect, negatively related to stable negative affect, and was mediated through stable affect in influencing resilience, well-being and distress. Thus, while a good sense of humor can lead to greater resilience and better psychological health, the current results, focusing on stable affect, find only self-enhancing humor provides reliable benefits.

An Energy Optimization Management Method of the Microgrid Based on Priority Ranking

Energy optimization management can realize optimal operation of the microgrid, to meet the requirements of economic operation, power supply reliability and environmental benefit, etcetera. Artificial intelligent algorithms are most widely used to solve this problem currently. In order to avoid the weaknesses of intelligent algorithms, this paper puts forward a simple and practical method based on priority ranking. A energy optimization management model of a grid-connected microgrid is established. Using the priority ranking method, optimal operation schemes under different optimization strategies are figured out. The analysis and discussion of optimal operation schemes and the comparison with the optimization result of particle swarm optimization (PSO) indicate that the method based on priority ranking is simple, effective and practical.

Overhead Line Preventive Maintenance Strategy Based on Condition Monitoring and System Reliability Assessment

This paper presents a maintenance strategy for overhead lines based on condition monitoring and system reliability assessment. A quantitative relationship between the condition monitoring data and failure rate of overhead lines is established. The system reliability is evaluated using monitoring data; the reliability benefit due to the maintenance of each line is quantified; and the maintenance ranking order is created using the benefit/cost ratio index. The proposed strategy can provide the largest reliability improvement at the lowest maintenance cost and within budget. Case studies were performed on a 182-bus, 5474-MW transmission system located in southwest China.

Avaliação de Competências em uma Instituição Hospitalar: A Visão de Avaliados e Avaliadores

Este artigo tem como objetivo analisar a visão de avaliados e avaliadores a respeito do processo de avaliação de desempenho baseado em competências, de uma instituição hospitalar. A pesquisa possui natureza predominantemente qualitativa, cuja estratégia deu-se pelo estudo de caso. Os procedimentos utilizados para coleta de dados foram: análise documental, questionários e entrevistas semiestruturadas. Para a análise das respostas obtidas no questionário, foi utilizado o tratamento estatístico descritivo dos dados. As entrevistas, por sua vez, foram interpretadas por meio da análise de discurso. Ambas as análises confluíram na triangulação de métodos de pesquisa. Foram evidenciados pontos fortes e oportunidades de melhoria nos processos de avaliação de desempenho executados pela organização. Além disso, discutiu-se o entendimento comum por parte dos usuários sobre seus significados e sobre a sua capacidade de aprimorar práticas atuais e que existem benefícios confiáveis e válidos na aplicação deste tipo de ferramenta. Destacou-se ainda a relevância da possibilidade de revisitar os processos de avaliação de forma a serem mais efetivos e condizentes com as expectativas organizacionais e individuais. Pretendeu-se com esta pesquisa contribuir para a afirmação da necessária aproximação da academia com a realidade de gestão, facilitando a conversação e refletindo benefícios para ambas.

Urban Planning and Application in Modern Tram Systems Evaluation

This paper reviewed the applicability and some problem on Modern tram system, stating the integrated system of modern tram system and the evaluation model as well as the indicators system for it,approach serial problems and key rules for city traffic construction for modern rail tram system. The Recommendations are: Modern tram system planning and design should begin from the applicability, economy, safe and reliable technology and social benefits to comprehensive analysis and evaluation on four aspects. Based on successful experiences, with its technology applications, system design, and layout of urban transport planning, establishing and perfecting the supporting technical regulations, standards, obtain experience through case study,in which devote major efforts to developing traffic for green,Security and humanistic.

No more electrical infrastructure

We consider the use of fuel cells for powering data centers, based on benefits in reliability, capital and operational costs, and reduced environmental emissions. Using fuel cells effectively in data centers introduces several challenges and we highlight key research questions for designing a fuel cell based data center power distribution system. We analyze a specific configuration in the design space to quantify the cost benefits for a large scale data center, for the most mature and commonly deployed fuel cell technology, achieving over 20% reduction in costs using conservative projections.

Combining a dynamic battery model with high-resolution smart grid data to assess microgrid islanding lifetime

In this paper, we use experimental data collected from an Austin, Texas smart grid test bed with a system-level battery energy storage model to assess the lifetime of batteries in a microgrid operating in islanded mode during a distribution-level outage. We consider a hypothetical microgrid consisting of 21 single-family detached homes and three transformer-level community energy storage (CES) battery units ranging in size from 25kWh to 75kWh. To describe the performance of CES batteries, we implement a dynamic behavioral circuit model capable of describing voltage transients and rate-capacity effects. We use one-minute electricity production and consumption data collected from the smart grid test bed in 2012 to assess how the timing of an electric outage affects the islanding lifetime of a residential microgrid. We contrast our results with the average outage duration reported by U.S. electric utilities to quantify how often a residential microgrid could withstand a typical outage. Our results show that increasing the amount of rooftop PV in a residential microgrid does not significantly increase how often it can withstand an average-duration outage. However, combining PV with CES extends the median islanding lifetime by up to 11.6h during morning outages. Based on our results, 50kWh CES provides the best tradeoff between the cost of a CES system and its reliability benefit, allowing downstream loads to withstand an average-duration outage approximately 93% of the time.

A Maintenance Policy Model Based on Time-Variant Reliability

A maintenance policy model based on time-variant reliability is put forward upon those mechanical systems which can carry on multiple maintenance in the whole life period, and the recurrence relations of the preventive maintenance intervals and reliability benefits is established. Two kinds of devices, one device’s mean time to failure complies with exponential distribution and another device’s mean time to failure meets the Weibull distribution, are taken as examples to get the approximate function expressions of the system's maintainability parameters of these devices through the curve fitting for data, analyze the system’s maintainability parameters and get the equipment’s maintenance policy model based on time-variant reliability. Examples verify the feasibility of the model.

Semprius Field Results and Progress in System Development

Semprius manufactures HCPV modules with printed microcells that provide cost, performance, and reliability benefits over conventional flat-plate modules. Recent module results exceed 35% efficiency at concentrator standard test condition and current factory built modules average 33%. Semprius has installed several different reference HCPV systems with apertures that range from 54 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> -140 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , suitable for commercial deployment. This paper outlines Semprius' system design approach and presents field results including system efficiency, power production, and tracker error. Results confirm an ac system efficiency of 30%. In addition, Semprius' performance model will be described and results presented.

In-vehicle monitoring and management for military vehicles’ integrated vetronics architectures

Both the rapid uptake of electronics utilisation for military vehicles (vetronics) and the trend in designing vehicles based on open standards and architectures (such as the UK MoD Generic Vehicle Architecture – Def Stan 23-09 GVA) have resulted in modern and future vehicles becoming highly complex platforms. Although most modern vehicles provide advanced diagnostics and health monitoring, most of these systems focus on end systems and applications and there has been little work on monitoring the infrastructure on which these systems operate. Monitoring the operational integrity of the vetronics that enable integration of vehicle subsystems and providing feedback to the crew offers safety and reliability benefits as it allows the crew to assess in real-time, the vehicle’s ability to complete its mission. This paper presents a novel approach to achieve in-vehicle Vetronics Integrity Monitoring and Management (VIMM). The paper highlights the requirements for a generic modular system, and presents both an architecture and proof-of-concept implementation.

It's a Dangerous Job, But Someone's Got to Do it: Policy Incentives to Mitigate the Impact of Operational Tort Liability

In industries where firms perform dangerous (but necessary) operations, liability costs - due to potential harm to third parties - can be significant. Firms may therefore find it optimal to exit the market, and this may lead to an inefficiently low number of incumbents. A social planner can discourage exit by offering appropriately designed subsidies. Ex ante subsidies defray the costs associated with making operations safer (e.g. funds to subsidize the purchase of safety equipment). Ex post subsidies mitigate the financial damages caused by an accident (e.g. funds to defray the cost of cleaning up a toxic spill). We consider a model where (i) firms have private information about their ability to improve reliability and (ii) reliability investments are unobservable. Our results challenge the view that, in the presence of moral hazard, ex post subsidies are always inferior to ex ante subsidies. We demonstrate that when the social value of reliability outweighs the benefit of increased competition, it is optimal to offer ex ante subsidies alone (i.e. to subsidize the cost of making operations safer). Conversely, when the benefits of competition outweigh the benefits of reliability, a combination of ex ante and ex post subsidies is optimal (i.e. not only to subsidize safer operations, but also to share the costs of a potential accident).

Value of Travel Time Savings

The I-85 express lanes in the Atlanta, Georgia, metropolitan region are among the newest high-occupancy-toll (HOT) facilities in the United States. This paper examines travelers’ value of time and their willingness to pay for the I-85 express lanes, compares travel times and travel time reliability in the general purpose and HOT lanes, and discusses the benefits users gain from the facility. The study examined 9 months of toll and travel time data for drivers who traversed the entire length of the express lane corridor during the morning and afternoon peak periods. Median values of travel time savings were $36/h in the southbound morning peak period and $26/h in the northbound afternoon peak period. The express lanes exhibited reliability benefits relative to the general-purpose lanes, but this study does not quantify the value of those benefits because of the lack of stated-preference data. The value that HOT lane users attributed to their time saved exceeded the time value obtained by using the average wage rate in the region. These results for the value of travel time were found to be similar to those for HOT lane implementations in other locations.

Diode Laser: A Perfect Option for Ankyloglossia Management

ABSTRACT Ankyloglossia or tongue tie is a developmental anomaly of tongue characterized by an abnormally short, thick lingual frenum resulting in limitation of tongue movement. Ankyloglossia can adversely affect feeding, speech articulation, and oral hygiene maintenance. This case reports of a 22-year-old male with tongue tie who complained of difficulty in speech following which he underwent lingual frenectomy procedure with laser, without any complications. Diode lasers are compact and portable in design with efficient and reliable benefits for use in soft-tissue oral surgical procedure. How to cite this article Saini R, Aljuboori MJ, Dagna A, Pithon MM. Diode Laser: A Perfect Option for Ankyloglossia Management. Int J Experiment Dent Sci 2014;3(2):115-116.

DG Placements Impact on the Reliability of Typical Industrial Distribution System In Saudi Arabia

Electrical Distribution systems that are usually radially configured with one utility power source are inherently exposed to higher rates of outages and interruptions due to the fact that failures of system components including transformers, breakers and switching devices along with fault conditions caused by different conditions are not preventable but rather improvable. Historically at Saudi Arabia (SA), many industrial and residential distribution networks suffered from the problems incurred by the utility grid connection including equipment failure, low power quality or human, animal and weather conditions. The fact that the large‐size, the growing demand and the cost with the time requirements for enhancements projects have made distributed generation (DG) in all its application, namely, online or backup to play a key role in the residential, commercial and industrial sectors of the power system. In this paper, the value of DG installed as an online power source of typical industrial distribution network at SA (Abqaiq) is quantified by reliability indices that include SAIDI, CAIDI and ENS. The study outcomes will provide power system engineers with the sense of the reliability benefits of DGs penetration and an approach to assess its installations based on different factors such as the size and location.

A 20-min nap in athletes changes subsequent sleep architecture but does not alter physical performances after normal sleep or 5-h phase-advance conditions

The aim of the study was to examine the effects of a post-prandial 20 min nap on a short-term physical exercise and subsequent sleep in athletes keeping their usual sleep schedules and in 5-h phase-advance condition. Sixteen healthy young male athletes (age 22.2 ± 1.7 years, non-habitual nappers) participated in the study. After a baseline 8-h time in bed in normal and 5-h advanced sleep schedules, a standardized morning and lunch in a laboratory environment, subjects underwent either a nap (20 min of sleep elapsed from 3 epochs of stage 1 or 1 epoch of stage 2), or a rest without sleep by lying in a bed, between 13:00 and 14:00 hours in non-shifted condition or 08:00 and 09:00 hours in shifted condition, after which anaerobic exercises were performed twice 2 h apart. Core body temperature was recorded throughout the study period. The nap extended sleep onset latency from 6.72 ± 3.83 to 11.84 ± 13.44 min, after shifted condition but did not modify sleep architecture of the post-trial night among athletes, whether shifted or not. Moreover, napping did not improve physical performance but it delayed acrophase and batyphase of core body temperature rhythm parameters. Napping showed no reliable benefit on short-term performances of athletes exercising at local time or after a simulated jet lag.