7 research outputs found
Community structure and timing of sexual activity among adolescent girls in Nigeria
No full textFunding: This research was supported by funding from the Consortium for Advanced Research Training in Africa (CARTA), awarded to OS. CARTA is jointly led by the African Population and Health Research Center and the University of the Witwatersrand and funded by the Carnegie Corporation of New York (Grant No. G-19-57145), Sida (Grant No:54100113), Uppsala Monitoring Center, Norwegian Agency for Development Cooperation (Norad), and by the Wellcome Trust [reference no. 107768/Z/15/Z] and the UK Foreign, Commonwealth & Development Office, with support from the Developing Excellence in Leadership, Training and Science in Africa (DELTAS Africa) programme. For the purpose of open access, the author has applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission.Studies have linked the timing of sexual debut to unplanned pregnancies and sexually transmissible infections, including HIV. Current understandings of sexual debut among Nigerian adolescents focused on the roles of individual and familial characteristics. We leveraged the 2018 Nigeria Demographic and Health Survey data to examine how community features like affluence, ethnic diversity, and women empowerment may be associated with the timing of sexual debut among adolescent girls. The sample comprised 7449 adolescent girls who were usual residents in 6,505 households and 1,352 clusters or communities. Statistical associations between community characteristics and the onset of sexual debut were assessed using a two-level mixed-effects parametric survival model with Weibull distribution. We found that community affluence [aHR:0.43, 95%CI: 0.30–0.62] and community ethnic diversity [aHR: 0.63, 95%CI: 0.42–0.94] are associated with a lower hazard of sexual debut among adolescent girls. We also observed that women that married within the observation period had an earlier sexual initiation than those who were unmarried. The results disaggregated by marital status further shows that higher community level of women’s employment [aHR: 2.45, 95%CI: 1.38–4.38] and women’s education [aHR:1.85, 95%CI: 1.03–3.33] were associated with a higher hazard of sexual debut among unmarried adolescent girls but not married adolescent girls. Higher community affluence [aHR:0.40, 95%CI: 0.27–0.60] was also associated with a lower hazard of sexual debut among unmarried adolescent girls but not married adolescent girls. Our results illuminate the associated factors of the timing of sexual debut among adolescent girls that moves beyond individual characteristics to community characteristics.Peer reviewe
What to bid and when to stop
No full textNegotiation is an important activity in human society, and is studied by various disciplines, ranging from economics and game theory, to electronic commerce, social psychology, and artificial intelligence. Traditionally, negotiation is a necessary, but also time-consuming and expensive activity. Therefore, in the last decades there has been a large interest in the automation of negotiation, for example in the setting of e-commerce. This interest is fueled by the promise of automated agents eventually being able to negotiate on behalf of human negotiators.Every year, automated negotiation agents are improving in various ways, and there is now a large body of negotiation strategies available, all with their unique strengths and weaknesses. For example, some agents are able to predict the opponent's preferences very well, while others focus more on having a sophisticated bidding strategy. The problem however, is that there is little incremental improvement in agent design, as the agents are tested in varying negotiation settings, using a diverse set of performance measures. This makes it very difficult to meaningfully compare the agents, let alone their underlying techniques. As a result, we lack a reliable way to pinpoint the most effective components in a negotiating agent.There are two major advantages of distinguishing between the different components of a negotiating agent's strategy: first, it allows the study of the behavior and performance of the components in isolation. For example, it becomes possible to compare the preference learning component of all agents, and to identify the best among them. Second, we can proceed to mix and match different components to create new negotiation strategies., e.g.: replacing the preference learning technique of an agent and then examining whether this makes a difference. Such a procedure enables us to combine the individual components to systematically explore the space of possible negotiation strategies.To develop a compositional approach to evaluate and combine the components, we identify structure in most agent designs by introducing the BOA architecture, in which we can develop and integrate the different components of a negotiating agent. We identify three main components of a general negotiation strategy; namely a bidding strategy (B), possibly an opponent model (O), and an acceptance strategy (A). The bidding strategy considers what concessions it deems appropriate given its own preferences, and takes the opponent into account by using an opponent model. The acceptance strategy decides whether offers proposed by the opponent should be accepted.The BOA architecture is integrated into a generic negotiation environment called Genius, which is a software environment for designing and evaluating negotiation strategies. To explore the negotiation strategy space of the negotiation research community, we amend the Genius repository with various existing agents and scenarios from literature. Additionally, we organize a yearly international negotiation competition (ANAC) to harvest even more strategies and scenarios. ANAC also acts as an evaluation tool for negotiation strategies, and encourages the design of negotiation strategies and scenarios.We re-implement agents from literature and ANAC and decouple them to fit into the BOA architecture without introducing any changes in their behavior. For each of the three components, we manage to find and analyze the best ones for specific cases, as described below. We show that the BOA framework leads to significant improvements in agent design by wining ANAC 2013, which had 19 participating teams from 8 international institutions, with an agent that is designed using the BOA framework and is informed by a preliminary analysis of the different components.In every negotiation, one of the negotiating parties must accept an offer to reach an agreement. Therefore, it is important that a negotiator employs a proficient mechanism to decide under which conditions to accept. When contemplating whether to accept an offer, the agent is faced with the acceptance dilemma: accepting the offer may be suboptimal, as better offers may still be presented before time runs out. On the other hand, accepting too late may prevent an agreement from being reached, resulting in a break off with no gain for either party. We classify and compare state-of-the-art generic acceptance conditions. We propose new acceptance strategies and we demonstrate that they outperform the other conditions. We also provide insight into why some conditions work better than others and investigate correlations between the properties of the negotiation scenario and the efficacy of acceptance conditions.Later, we adopt a more principled approach by applying optimal stopping theory to calculate the optimal decision on the acceptance of an offer. We approach the decision of whether to accept as a sequential decision problem, by modeling the bids received as a stochastic process. We determine the optimal acceptance policies for particular opponent classes and we present an approach to estimate the expected range of offers when the type of opponent is unknown. We show that the proposed approach is able to find the optimal time to accept, and improves upon all existing acceptance strategies.Another principal component of a negotiating agent's strategy is its ability to take the opponent's preferences into account. The quality of an opponent model can be measured in two different ways. One is to use the agent's performance as a benchmark for the model's quality. We evaluate and compare the performance of a selection of state-of-the-art opponent modeling techniques in negotiation. We provide an overview of the factors influencing the quality of a model and we analyze how the performance of opponent models depends on the negotiation setting. We identify a class of simple and surprisingly effective opponent modeling techniques that did not receive much previous attention in literature.The other way to measure the quality of an opponent model is to directly evaluate its accuracy by using similarity measures. We review all methods to measure the accuracy of an opponent model and we then analyze how changes in accuracy translate into performance differences. Moreover, we pinpoint the best predictors for good performance. This leads to new insights concerning how to construct an opponent model, and what we need to measure when optimizing performance.Finally, we take two different approaches to gain more insight into effective bidding strategies. We present a new classification method for negotiation strategies, based on their pattern of concession making against different kinds of opponents. We apply this technique to classify some well-known negotiating strategies, and we formulate guidelines on how agents should bid in order to be successful, which gives insight into the bidding strategy space of negotiating agents. Furthermore, we apply optimal stopping theory again, this time to find the concessions that maximize utility for the bidder against particular opponents. We show there is an interesting connection between optimal bidding and optimal acceptance strategies, in the sense that they are mirrored versions of each other.Lastly, after analyzing all components separately, we put the pieces back together again. We take all BOA components accumulated so far, including the best ones, and combine them all together to explore the space of negotiation strategies.We compute the contribution of each component to the overall negotiation result, and we study the interaction between components. We find that combining the best agent components indeed makes the strongest agents. This shows that the component-based view of the BOA architecture not only provides a useful basis for developing negotiating agents but also provides a useful analytical tool. By varying the BOA components we are able to demonstrate the contribution of each component to the negotiation result, and thus analyze the significance of each. The bidding strategy is by far the most important to consider, followed by the acceptance conditions and finally followed by the opponent model.Our results validate the analytical approach of the BOA framework to first optimize the individual components, and then to recombine them into a negotiating agent
Smart prepaid energy metering system to detect energy theft with facility for real time monitoring
No full textElectricity theft remains a huge loss incurred by electricity distribution companies. This theft arises majorly because of activities carried out by consumers such as energy-meter by-passing, energy-meter tampering etc. This research study offers an approach for handling energy meter by-passing and tampering. The system design is based on the monitoring of the readings of two current sensors by a programmed microcontroller. While one of the current sensors monitors the current drawn by the user’s load, the latter installed before the meter monitors current drawn by all loads. Any discrepancy between the values read, indicates theft. A momentary switch is also installed in the meter to trigger the meter once it is tampered with. Furthermore, the user is provided with a remote access to the energy meter for recharging energy units and for monitoring energy consumption. It was observed that the system accurately measured load consumption and detect any attempt to by-pass or tamper with the energy meter. Lastly, all unscrupulous attempts were reported using GSM technology
The association between family adversity and youth mental health outcomes
No full textDATA AVAILABILITY STATEMENT : The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.BACKGROUND: The association between family adversity and young people's mental health outcomes in communities that experience economic instability has not been well explored in the South African context. Furthermore, the overtime interaction between resilience factors, family adversity, and young people's psychological functioning in African settings, like South Africa, is under‐investigated.
PURPOSE: This study investigates the relationship between family adversity and conduct problems and depression at two‐time points in a sample of youths in two South African communities stressed by their dependency on economically volatile oil and gas industries.
METHOD: This article draws on longitudinal data generated by the Resilient Youth inStressed Environments (RYSE) study in South Africa, which included 914 and 528(wave 1 and 3) adolescents and emerging adults (14–27‐year‐olds;Mage = 18.36years) living in Secunda/eMbalenhle and Sasolburg/Zamdela. Participants were sampled at baseline (wave 1) and 18–24 months later (wave 3). They self-reported experiences of community violence, family adversity, resilience‐enabling resources, conduct difficulties, and depression symptoms. Regression analyses were used to examine the unadjusted and adjusted association of family adversity on conduct problems and depression.
RESULTS: About 60% of participants reported high family adversity. Regressions, however, revealed no association between family adversity and conduct problems and depression cross‐sectionally and over time. Individual resilience, biological sex, and experience of victimization in the community, however, were associated with conduct difficulty while all three resilience factors were associated with decreased depression among participants.
CONCLUSION: Our study sheds light on the risk and protective factors for mental health outcomes of adolescents and youths who reside in volatile, turbulent communities and experience ongoing familial challenges. To effectively support the mental well‐being of young individuals in such contexts, interventions must consider the potential potential of the resilience factors they aim to strengthen.The Canadian Institutes of Health Research and the National Research Foundation.https://onlinelibrary.wiley.com/journal/10959254Educational Psycholog
Decade of research into the acceptability of interventions aimed at improving adolescent and youth health and social outcomes in Africa: a systematic review and evidence map
No full textOBJECTIVE:
Interventions aimed at improving adolescent health and social outcomes are more likely to be successful if the young people they target find them acceptable. However, no standard definitions or indicators exist to assess acceptability. Acceptability research with adolescents in low-and-middle-income countries (LMICs) is still limited and no known reviews systhesise the evidence from Africa. This paper maps and qualitatively synthesises the scope, characteristics and findings of these studies, including definitions of acceptability, methods used, the type and objectives of interventions assessed, and overall findings on adolescent acceptability.
DESIGN:
We conducted a systematic review of peer-reviewed studies assessing intervention acceptability with young adults (aged 10–24) in Africa, published between January 2010 and June 2020.
DATA SOURCES:
Web of Science, Medline, PsycINFO, SociIndex, CINAHL, Africa-wide, Academic Search Complete and PubMed were searched through July 2020.
ELIGIBILITY CRITERIA FOR SELECTING STUDIES:
Papers were selected based on the following inclusion criteria: if they (1) reported primary research assessing acceptability (based on the authors’ definition of the study or findings) of one or more intervention(s) with adolescents and young adults 10–24; (2) assessed acceptability of intervention(s) aimed at positively influencing one or more development outcome(s), as defined by sustainable development goal (SDG) indicators; (3) reported on research conducted in Africa; (4) were in the English Language; (5) were peer-reviewed and and (6) were published between 1 January 2010 and 30 June 2020.
DATA EXTRACTION AND SYNTHESIS:
Abstracts were reviewed independently by the two first authors to determine relevance. Full text of potentially eligible studies were retrieved and independently examined by the same two authors; areas of disagreement or lack of clarity were resolved through discussion by the two authors and—where necessary—the assessment of a third author.
RESULTS:
55 studies were considered eligible for inclusion in the review. Most studies were conducted in Southern Africa, of which 32 jointly in South Africa and Uganda. The majority of interventions assessed for acceptability could be classified as HIV or HPV vaccine interventions (10), E-health (10), HIV testing interventions (8), support group interventions (7) and contraceptive interventions (6). The objectives of most interventions were linked to SDG3, specifically to HIV and sexual and reproductive health. Acceptability was overall high among these published studies. 22 studies provided reasons for acceptability or lack thereof, some specific to particular types of interventions and others common across intervention types.
CONCLUSIONS:
Our review exposes considerable scope for future acceptability research and review work. This should include extending acceptability research beyond the health (and particularly HIV) sector and to regions in Africa where this type of research is still scarce; including adolescents earlier, and potentially throughout the intervention process; further conceptualising the construct of acceptability among adolescents and beyond; and examining the relationship between acceptability and uptake
Artificial Neural Network-Based Capacitance Prediction Model for Optimal Voltage Control of Stand-alone Wind-Driven Self-Excited Reluctance Generator
No full textThis paper presents an Artificial Neural Network (ANN) model to predict the excitation capacitance value necessary to sustain the generated voltage of a wind-driven self-excited reluctance generator (WDSERG) within preferred limits. The network was trained, validated and tested with input data which comprises load impedances, power factor and wind speed values and a corresponding output data consisting of the excitation capacitance for each input condition. A mean square error value of less than 0.11 and an R-value of more than 0.999 were obtained for the network. These indicate a very accurate ANN training. The network was then utilized in the complete model of WDSERG under diverse input states of wind speed and load variation. The predicted capacitance value obtained from the network provides the required excitation to keep the generated phase voltage at a preferred constant level of 220±5 V under each input condition. The results depict the effectiveness of the neural network application to provide excitation capacitance control for the WDSERG output voltage when varying wind speed and load profile are considered. The method proposed in this work can provide a basis for the design of a variable capacitor to keep the generated voltage of wind-driven SERG within desired limits despite wind speed and load variation
