Fuzzy Ranking Methods and Their Applications

Fuzzy ranking is a procedure used to compare and order a sequence of fuzzy sets (FSs). It is an essential step in fuzzy decision making problems before a final decision can be drawn. While many fuzzy ranking methods are available in the literature, a generic method that can provide appropriate and satisfactory solutions across a variety of situations has yet to be developed. Many existing methods are limited to rank either type-l fuzzy sets (TIFSs) or interval type-2 fuzzy sets (lT2FSs), and only few methods can flexibility handle both types of FSs. In particular, fuzzy ranking becomes complicated when FSs are represented by possibility distributions, which can overlap with one another. In this thesis, two new fuzzy ranking methods with different purposes are proposed. The first method ranks both TIFSs and IT2FSs by considering ranking and weighting issues, while the second ranks both TIFSs and IT2FSs by integrating decision makers' viewpoints. Besides that, it is important for a fuzzy ranking method to satisfy a set of reasonable fuzzy ordering properties. As a result, the capability of the proposed fuzzy ranking methods in fulfilling the relevant properties is analyzed and discussed. The usefulness of both methods is demonstrated using real-world applications. The results positively indicate efficacy of the proposed fuzzy ranking methods in solving fuzzy ranking problem as well as complex decision making problems in practical environments

A perceptual computing-based approach for peer assessment

Peer assessment is useful for assessing an individual's contribution in a collaborative learning task. It is commonly used in institutions of higher education as normally each class has a large number of students. Peer assessment allows students to assess their group members' contributions. It also helps the instructor to arrive at an assessment that reflects individual's effort in a collaborative learning task. In this paper, a perceptual computing (Per-C)-based peer assessment procedure is investigated. The assessment adopts vague and imprecise words in the evaluation process. Per-C is selected because it allows uncertainties of words to be considered in the decision making process. A real case study is conducted to demonstrate the effectiveness of the proposed method. The results show that the use of Per-C in peer assessment is important

A New Sign Distance-Based Ranking Method for Fuzzy Numbers

In this paper, a new sign distance-based ranking method for fuzzy numbers is proposed. It is a synthesis of geometric centroid and sign distance. The use of centroid and sign distance in fuzzy ranking is not new. Most existing methods (e.g., distance-based method [9]) adopt the Euclidean distance from the origin to the centroid of a fuzzy number. In this paper, a fuzzy number is treated as a polygon, in which a new geometric centroid for the fuzzy number is proposed. Since a fuzzy number can be represented in different shapes with different spreads, a new dispersion coefficient pertaining to a fuzzy number is formulated. The dispersion coefficient is used to fine-tune the geometric centroid, and subsequently sign distance from the origin to the tuned geometric centroid is considered. As discussed in [5-9], an ideal fuzzy ranking method needs to satisfy seven reasonable fuzzy ordering properties. As a result, the capability of the proposed method in fulfilling these properties is analyzed and discussed. Positive experimental results are obtained

A new dempster-shafer theory-based method with fuzzy targets for fuzzy sets ranking

In this paper, a new Fuzzy Set (FS) ranking method (for type-1 and interval type-2 FSs), which is based on the Dempster-Shafer Theory (DST) of evidence with fuzzy targets, is investigated. Fuzzy targets are adopted to reflect human viewpoints on fuzzy ranking. Two important measures in DST, i.e., the belief and plausibility measures, are used to rank FSs. The proposed approach is evaluated with several benchmark examples. The use of the belief and plausibility measures in fuzzy ranking are discussed and compared. We further analyze the capability of the proposed approach in fulfilling six reasonable fuzzy ordering properties as discussed in [9]-[11]

A new fuzzy peer assessment methodology for cooperative learning of students

In this paper, a new fuzzy peer assessment methodology that considers vagueness and imprecision of words used throughout the evaluation process in a cooperative learning environment is proposed. Instead of numerals, words are used in the evaluation process, in order to provide greater flexibility. The proposed methodology is a synthesis of perceptual computing (Per-C) and a fuzzy ranking algorithm. Per-C is adopted because it allows uncertainties of words to be considered in the evaluation process. Meanwhile, the fuzzy ranking algorithm is deployed to obtain appropriate performance indices that reflect a student's contribution in a group, and subsequently rank the student accordingly. A case study to demonstrate the effectiveness of the proposed methodology is described. Implications of the results are analyzed and discussed. The outcomes clearly demonstrate that the proposed fuzzy peer assessment methodology can be deployed as an effective evaluation tool for cooperative learning of students

Technologies for removing pharmaceuticals and personal care products (PPCPs) from aqueous solutions: Recent advances, performances, challenges and recommendations for improvements

In recent years, the removal of pharmaceutical and personal care products (PPCPs) from aqueous solutions has been gaining a lot of attention from researchers throughout the world. This is particularly due to the concern about their potential hazards and toxicities, as they are classified as emerging contaminants. Thus, there is an increasing need to investigate removal technologies for PPCPs at a deeper and more holistic level. This review aims to provide the latest developments in removal technologies for PPCPs. It first succinctly describes the types, characteristics, and hazards of PPCPs on the environment and human health. It then comprehensively covers a wide range of technologies for removing PPCPs from aqueous solutions, comprising the adsorption process (using carbon-based adsorbents, plant biomasses, clay and clay minerals, silica-based adsorbents, zeolite-based adsorbents, polymers and resins, and hybrid adsorbents), advanced oxidation processes (AOPs) (photocatalysis, Fenton or photo-Fenton or electro-Fenton, ozonation, ultrasonication, electrochemical oxidation, persulfate oxidation), membrane separation processes (ultrafiltration, nanofiltration, reverse osmosis), biodegradation processes (bacteria, fungi, and algae), and hybrid treatment (adsorption-AOP, AOP-membrane, membrane-biodegradation, and others). According to the specific experimental conditions, the reported removal efficiencies for adsorption, AOPs, membrane processes, biodegradation processes and hybrid treatment were 40–100%, 40–100%, 3–100%, 14–100% and 5–100%, respectively. This review paper also highlights the challenges in this field of research, particularly incomplete removal of certain PPCPs, high costs of some treatment technologies and generally insufficient understanding on the removal kinetics and mechanisms of PPCPs. This review offers recommendations for future works to further advance the technical performances to eventually realize the wider application of these technologies at the industrial scale

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

An Economic Solution to Optimize Performance of Photovoltaic Modules under Partial Shading

This paper investigates the effects of partial shading pertaining to photovoltaic (PV) modules and subsequently a solution that aims to minimize the effects and optimize the performance of PV modules is proposed. The concept of the solution is to integrate boost and buck converters into an electronic control system. The proposed system is simple and economic solution as it integrates cheap and easy available electronic components such as microcontrollers, capacitors, transistors and inductors. To validate the effectiveness of proposed system, a measuring instrument, namely NI cFP-1808 is used to perform the electrical characteristic analyses or known as I-V and P-V curve analyses. Furthermore, an outdoor experiment was conducted to examine the practicality of the proposed system in tackling real-world conditions. Experimental results showed that the proposed system improves the performance of the PV modules by 82.9% compared to the controlled experiment. In short, the effectiveness and practicality of the proposed system is proven with experiment results

A new fuzzy peer assessment methodology for cooperative learning of students

In this paper, a new fuzzy peer assessment methodology that considers vagueness and imprecision of words used throughout the evaluation process in a cooperative learning environment is proposed. Instead of numerals, words are used in the evaluation process, in order to provide greater flexibility. The proposed methodology is a synthesis of perceptual computing (Per-C) and a fuzzy ranking algorithm. Per-C is adopted because it allows uncertainties of words to be considered in the evaluation process. Meanwhile, the fuzzy ranking algorithm is deployed to obtain appropriate performance indices that reflect a student\u27s contribution in a group, and subsequently rank the student accordingly. A case study to demonstrate the effectiveness of the proposed methodology is described. Implications of the results are analyzed and discussed. The outcomes clearly demonstrate that the proposed fuzzy peer assessment methodology can be deployed as an effective evaluation tool for cooperative learning of students