Critical Assessment of the Foundations of Power Transmission and Distribution Reliability Metrics and Standards

The U.S. federal government regulates the reliability of bulk power systems, while the reliability of power distribution systems is regulated at a state level. In this article, we review the history of regulating electric service reliability and study the existing reliability metrics, indices, and standards for power transmission and distribution networks. We assess the foundations of the reliability standards and metrics, discuss how they are applied to outages caused by large exogenous disturbances such as natural disasters, and investigate whether the standards adequately internalize the impacts of these events. Our reflections shed light on how existing standards conceptualize reliability, question the basis for treating large‐scale hazard‐induced outages differently from normal daily outages, and discuss whether this conceptualization maps well onto customer expectations. We show that the risk indices for transmission systems used in regulating power system reliability do not adequately capture the risks that transmission systems are prone to, particularly when it comes to low‐probability high‐impact events. We also point out several shortcomings associated with the way in which regulators require utilities to calculate and report distribution system reliability indices. We offer several recommendations for improving the conceptualization of reliability metrics and standards. We conclude that while the approaches taken in reliability standards have made considerable advances in enhancing the reliability of power systems and may be logical from a utility perspective during normal operation, existing standards do not provide a sufficient incentive structure for the utilities to adequately ensure high levels of reliability for end‐users, particularly during large‐scale events.     

Explaining Family Change and Variation: Challenges for Family Demographers

Twenty years ago, the National Institute of Child Health and Human Development (NICHD) issued a request for proposals that resulted in the National Survey of Families and Households (NSFH), a unique survey valuable to a wide range of family scholars. This paper describes the efforts of an interdisciplinary group of family demographers to build on the progress enabled by the NSFH and many other theoretical and methodological innovations. Our work, also supported by NICHD, will develop plans for research and data collection to address the central question of what causes family change and variation. We outline the group's initial assessments of orienting frameworks, key aspects of family life to study, and theoretical and methodological challenges for research on family change. Finally, we invite family scholars to follow our progress and to help develop this shared public good.     

Human Immunodeficiency Virus (HIV) Seropositive Homeless Men: Behavioral and Social Characteristics

Homeless persons living in US. innercities are at risk for human immunodeficiency virus (HW) infection, but few studies have examined the continued risk behaviors of HIV infected homeless men. We investigated the sexual behavior of 32 homeless men who had tested HIV seropositive. Twenty-five percent of HW positive men reported a history of injection drug use, 34% had sex with men, over 40% had participated in commercial sex, and 59% had been treated for a non-HIV sexually transmitted disease. HIV seropositive men also reported recent sexual behavior, with 62% having sex in the previous month and 50% currently sexually active. Condom use was inconsistent among seropositive men; 44% of vaginal and 50% of anal intercourse occasions in the preceding three months did not involve condoms, and 28% of HW seropositive men did not use a condom during their most recent sexual encounter. Substance use was frequently associated with unprotected sexual behavior among HW seropositive men. Finally, measures of life satisfaction showed that HIV seropositive men were most satisfied with their relationships, mental health, and spiritual well being. These data suggest a need for intensive behavioral.interventions tailored for homeless HW infected men and we recommend that existing substance use treatment and holistic care be incorporated into behavioral interventions for HW infected men.     

Review and Evaluation of the J100-10 Risk and Resilience Management Standard for Water and Wastewater Systems

Risk analysis standards are often employed to protect critical infrastructures, which are vital to a nation's security, economy, and safety of its citizens. We present an analysis framework for evaluating such standards and apply it to the J100-10 risk analysis standard for water and wastewater systems. In doing so, we identify gaps between practices recommended in the standard and the state of the art. While individual processes found within infrastructure risk analysis standards have been evaluated in the past, we present a foundational review and focus specifically on water systems. By highlighting both the conceptual shortcomings and practical limitations, we aim to prioritize the shortcomings needed to be addressed. Key findings from this study include (1) risk definitions fail to address notions of uncertainty, (2) the sole use of “worst reasonable case” assumptions can lead to mischaracterizations of risk, (3) analysis of risk and resilience at the threat-asset resolution ignores dependencies within the system, and (4) stakeholder values need to be assessed when balancing the tradeoffs between risk reduction and resilience enhancement.     

Student Veterans: Meaning in Life,Negative Career Thoughts,and Depression

Student veterans may experience challenges as they transition from military to student life, including adjusting to the academic environment, coping with mental health concerns, and redefining their identities. Research indicates that veterans may have difficulty finding meaning and purpose outside of the military (Brenner et al., 2008; Doenges, 2011). This study explored variables that may affect meaning and purpose in student veterans' lives, specifically negative career thoughts and depression. One hundred thirty-two student veterans at U.S. institutions were surveyed. The results revealed that both negative career thoughts and depression were statistically significant predictors (p < .001) of the presence of meaning in life, with 46% of the variance in the presence of meaning in life scores accounted for by participants' negative career thinking and depression levels. Pearson correlations indicated that all variables were statistically significant (p < .01). Future research could explore how other career readiness and self-assessment constructs are related to meaning and purpose in student veterans' lives, as well as the intersection of mental health and career factors. Interventions that focus both on the presence of negative career thoughts and depressive symptomatology may positively influence student veterans' report of meaning and purpose in life.     

Climate,agriculture, and hunger: statistical prediction of undernourishment using nonlinear regression and data-mining techniques

An estimated 1 billion people suffer from hunger worldwide, and climate change, urbanization, and globalization have the potential to exacerbate this situation. Improved models for predicting food security are needed to understand these impacts and design interventions. However, food insecurity is the result of complex interactions between physical and socio-economic factors that can overwhelm linear regression models. More sophisticated data-mining approaches could provide an effective way to model these relationships and accurately predict food insecure situations. In this paper, we compare multiple regression and data-mining methods in their ability to predict the percent of a country's population that suffers from undernourishment using widely available predictor variables related to socio-economic settings, agricultural production and trade, and climate conditions. Averaging predictions from multiple models results in the lowest predictive error and provides an accurate method to predict undernourishment levels. Partial dependence plots are used to evaluate covariate influence and demonstrate the relationship between food insecurity and climatic and socio-economic variables. By providing insights into these relationships and a mechanism for predicting undernourishment using readily available data, statistical models like those developed here could be a useful tool for those tasked with understanding and addressing food insecurity.     

Modeling Logistic Performance in Quantitative Microbial Risk Assessment

In quantitative microbial risk assessment (QMRA), food safety in the food chain is modeled and simulated. In general, prevalences, concentrations, and numbers of microorganisms in media are investigated in the different steps from farm to fork. The underlying rates and conditions (such as storage times, temperatures, gas conditions, and their distributions) are determined. However, the logistic chain with its queues (storages, shelves) and mechanisms for ordering products is usually not taken into account. As a consequence, storage times—mutually dependent in successive steps in the chain—cannot be described adequately. This may have a great impact on the tails of risk distributions. Because food safety risks are generally very small, it is crucial to model the tails of (underlying) distributions as accurately as possible. Logistic performance can be modeled by describing the underlying planning and scheduling mechanisms in discrete-event modeling. This is common practice in operations research, specifically in supply chain management. In this article, we present the application of discrete-event modeling in the context of a QMRA for  Listeria monocytogenes  in fresh-cut iceberg lettuce. We show the potential value of discrete-event modeling in QMRA by calculating logistic interventions (modifications in the logistic chain) and determining their significance with respect to food safety.     

Using Task Clarification,Goal Setting,and Feedback to Decrease Table Busing Times in a Franchise Pizza Restaurant

The current study investigated the effects of task-clarification, and manager verbal and graphic feedback on employee busing times at a pizza restaurant. Using an ABC design, task-clarification was provided in a memo, which described the process, priority, and goal time of busing. The busing time decreased slightly, from an average of 315 seconds during baseline to an average of 284 seconds after the task clarification memo. The majority of this change was accounted for by servers decreasing the time it took them to arrive at the table to begin busing. Subsequent to the employee memo, group feedback was administered in the form of verbal feedback and a weekly graph of average server busing times. This feedback was associated with reductions in busing time to an average 152 seconds. Changes in the feedback phase were caused almost exclusively by reductions in the time it took to clean the table once the server was there. A reversal to near-baseline busing times was observed in a follow-up phase. Prebusing and cross-busing were not associated with shorter busing times.     

A review of the effectiveness of empowering leadership

Based on a review of empirical literature on empowering leadership, given incongruent and mixed results, the current work suggests reconsidering the effectiveness of empowering leadership. We propose a framework for examining the effectiveness of empowering leadership that considers: 1) feasibility of non-linear main effects of empowering leadership on work-related outcomes, 2) possibility of reverse causation between empowering leadership and work-related outcomes, 3) potential contradictory mediating mechanisms through which empowering leadership influences work-related outcomes, 4) consideration of boundary conditions which could alter the relationships between empowering leadership and work-related outcomes, and 5) consideration of levels-of-analysis and multilevel issues in empowering leadership. Our framework considers the multifaceted nature of empowering leadership and offers a guiding tool for advancing future research in this area.     

A program of research with Hispanic and African American families: three decades of intervention development and testing influenced by the changing cultural context of Miami

In this article we summarize work with poor, inner-city Hispanic and African American families conducted at the University of Miami Center for Family Studies. We elucidate ways in which this research program has paralleled the treatment development paradigm and has been responsive to changes in local demographics. Specific cultural issues pertaining to Hispanics and African Americans are discussed in light of treatment development and implementation. Future directions and challenges for working with poor, inner-city minority families are addressed.