A new fuzzy ratio and its application to the single input rule modules connected fuzzy inference system

The principle of ratios has been applied to many real world problems, e.g. the part-to-part and part-to-whole ratio formulations. As it is difficult for humans to provide an exact ratio in many real situations, we introduce a fuzzy ratio in this paper. We use some notions from fuzzy arithmetic to analyze fuzzy ratios captured from humans. An application of the formulated fuzzy ratio to a Single Input Rule Modules connected Fuzzy Inference System (SIRMs-FIS) is demonstrated. Instead of using a precise weight, fuzzy sets are employed to represent the relative importance of each rule module. The resulting fuzzy weights are explained as a fuzzy ratio on a weight domain. In addition, a new SIRMs-FIS model with fuzzy weights and part-to-whole fuzzy ratio is devised. A simulated example is presented to clarify the proposed SIRM-FIS model.

Research of a new type rectifier and voltage-multiplier piezoelectric energy harvester circuit

Traditional rectifier circuit can convert AC to DC, but some disadvantages can't be avoided, such as small output current, high power consumption, low conversion efficiency. This paper designs a new type of rectifier voltage-multiplier circuit named MR MOS circuit. It uses a low let-through resistance MOS tube to replace the conventional rectifier diode, and adds the voltage-multiplying factor to the synchronous input port. Therefore, it can improve the rectifier effect and increase the output voltage. By the simulation result of Synopsys Saber Platform, it shows that the new type circuit can implement the rectification and voltage-multiplying by the simulating output pulse voltage of nano fiber made in Deakin University as the source of excitation. It can provide the basic theoretical of the piezoelectric energy harvester (PEH) development, and has certain reference significance to the development of piezoelectricity technology. © (2014) Trans Tech Publications.

Fuzzy portfolio allocation models through a new risk measure and fuzzy sharpe ratio

A new portfolio risk measure that is the uncertainty of portfolio fuzzy return is introduced in this paper. Beyond the well-known Sharpe ratio (i.e., the reward-to-variability ratio) in modern portfolio theory, we initiate the so-called fuzzy Sharpe ratio in the fuzzy modeling context. In addition to the introduction of the new risk measure, we also put forward the reward-to-uncertainty ratio to assess the portfolio performance in fuzzy modeling. Corresponding to two approaches based on TM and TW fuzzy arithmetic, two portfolio optimization models are formulated in which the uncertainty of portfolio fuzzy returns is minimized, while the fuzzy Sharpe ratio is maximized. These models are solved by the fuzzy approach or by the genetic algorithm (GA). Solutions of the two proposed models are shown to be dominant in terms of portfolio return uncertainty compared with those of the conventional mean-variance optimization (MVO) model used prevalently in the financial literature. In terms of portfolio performance evaluated by the fuzzy Sharpe ratio and the reward-to-uncertainty ratio, the model using TW fuzzy arithmetic results in higher performance portfolios than those obtained by both the MVO and the fuzzy model, which employs TM fuzzy arithmetic. We also find that using the fuzzy approach for solving multiobjective problems appears to achieve more optimal solutions than using GA, although GA can offer a series of well-diversified portfolio solutions diagrammed in a Pareto frontier.

Expanding a successful community-based obesity prevention approach into new communities : challenges and achievements

OBJECTIVE: A previously successful community-based obesity prevention intervention with a focus on school settings was expanded into new communities with varying contexts. In order to understand the complexities involved in implementing health promotion activities in schools, this study examined experiences of school staff and project officers including barriers, contextual factors and achievements. METHODS: School environment assessments were conducted in schools across four Victorian communities with school staff (n=1-5 staff plus a trained researcher per group in 9 primary and 8 secondary schools) 12-18 months post-intervention. Process reports from project officers were also reviewed and analysed (n=4). RESULTS: School staff commonly reported time pressures as a barrier to implementation and project officers working within schools reported competing priorities and limited health promotion experience of staff; lack of stakeholder engagement; low participation in some activities and insufficient implementation time. Contextual factors included community socioeconomic status, student ethnicity and living rurally. Achievements included student and staff enjoyment from programme activities, staff capacity building, partnerships, embedding activities into existing infrastructure and programmes, and having consistent health-related messages repeated through a variety of strategies. CONCLUSIONS: Community-based interventions with a focus on school settings need to consider system level, organisational and contextual (i.e. socioeconomic, ethnicity, family and town characteristics) factors when expanding previously effective strategies into new communities. Implementation benefits may have added whole of school benefits in addition to child health. Focussing on overcoming the challenges experienced in this complex initiative is required for future interventions.