Heterogeneous Ant Colony Optimisation Methods and their Application to the Travelling Salesman and PCB Drilling Problems

Ant Colony Optimization (ACO) is an optimization algorithm that is inspired by the foraging behaviour of real ants in locating and transporting food source to their nest. It is designed as a population-based metaheuristic and have been successfully implemented on various NP-hard problems such as the well-known Traveling Salesman Problem (TSP), Vehicle Routing Problem (VRP) and many more. However, majority of the studies in ACO focused on homogeneous artificial ants although animal behaviour researchers suggest that real ants exhibit heterogeneous behaviour thus improving the overall efficiency of the ant colonies. Equally important is that most, if not all, optimization algorithms require proper parameter tuning to achieve optimal performance. However, it is well-known that parameters are problem-dependant as different problems or even different instances have different optimal parameter settings. Parameter tuning through the testing of parameter combinations is a computationally expensive procedure that is infeasible on large-scale real-world problems. One method to mitigate this is to introduce heterogeneity by initializing the artificial agents with individual parameters rather than colony level parameters. This allows the algorithm to either actively or passively discover good parameter settings during the search. The approach undertaken in this study is to randomly initialize the ants from both uniform and Gaussian distribution respectively within a predefined range of values. The approach taken in this study is one of biological plausibility for ants with similar roles, but differing behavioural traits, which are being drawn from a mathematical distribution. This study also introduces an adaptive approach to the heterogeneous ant colony population that evolves the alpha and beta controlling parameters for ACO to locate near-optimal solutions. The adaptive approach is able to modify the exploitation and exploration characteristics of the algorithm during the search to reflect the dynamic nature of search. An empirical analysis of the proposed algorithm tested on a range of Travelling Salesman Problem (TSP) instances shows that the approach has better algorithmic performance when compared against state-of-the-art algorithms from the literature

Symbiosis between the TRECVid benchmark and video libraries at the Netherlands Institute for Sound and Vision

Audiovisual archives are investing in large-scale digitisation efforts of their analogue holdings and, in parallel, ingesting an ever-increasing amount of born- digital files in their digital storage facilities. Digitisation opens up new access paradigms and boosted re-use of audiovisual content. Query-log analyses show the shortcomings of manual annotation, therefore archives are complementing these annotations by developing novel search engines that automatically extract information from both audio and the visual tracks. Over the past few years, the TRECVid benchmark has developed a novel relationship with the Netherlands Institute of Sound and Vision (NISV) which goes beyond the NISV just providing data and use cases to TRECVid. Prototype and demonstrator systems developed as part of TRECVid are set to become a key driver in improving the quality of search engines at the NISV and will ultimately help other audiovisual archives to offer more efficient and more fine-grained access to their collections. This paper reports the experiences of NISV in leveraging the activities of the TRECVid benchmark

Factors Associated with Health-related Quality of Life among Post-paralytic Polio Survivors in Nigeria

The purpose of this study was to assess Quality of Life (QOL), and examine its association with occupation and level of education among polio survivors. The study was a cross-sectional survey of polio survivors (N = 54) registered with the Post Paralytic Polio Survivors Association, living in Gusau, North Western Nigeria. The World Health Organization (WHO) QOL BREF 26 Items English version was used to assess QOL, while a biodata form was used to assess demographic variables. The data were analyzed using mean and standard deviation, Wilcoxon rank test and Kruskal-Wallis test. The level of significance was set at 0.05. The mean age of the participants was 22.4 ± 5.4 years and mean QOL scores were 45.2 ± 9.7, 54.8 ± 11.4, 41.3 ± 10.9 and 44.4 ± 12.1 in physical, psychological, social relationship and environmental domains, respectively. The participants’ overall perception of their QOL and health averaged 3.3 ± 0.8 and 3.6 ± 0.7, respectively. No significant association was observed between all the domains. Occupation status (P > 0.05) and educational level had no significant relationship with all the domains (P > 0.05). The findings of this study suggest that the QOL of polio survivors is not associated with their occupational status and level of education. It was suggested that follow-up research should try to clarify whether improving occupational and education status raises the QOL of polio survivors. Keywords: Polio, quality of life, survivor

Conclusions from CDF Results on CP Violation in D^0 \to \pi^+\pi^-, K^+K^- and Future Tasks

Within the Standard Model (SM) one predicts both direct and indirect CP violation in D^0 \to \pi^+\pi^-, K^+K^- transitions, although the effects are tiny: Indirect CP asymmetry cannot exceed O(10^{-4}), probably even O(10^{-5}); direct effects are estimated at not larger than 10^{-4}. At B factories direct and indirect asymmetries have been studied with /\tau_{D^0} ~ 1; no CP asymmetry was found with an upper bound of about 1%. CDF has shown intriguing data on CP violation in D^0 \to \pi^+\pi^- [K^+K^-] with /\tau_{D^0} ~ 2.4 [2.65]. Also, CDF has not seen any CP violation. For direct CP asymmetry, CDF has a sensitivity similar to the combination of the B factories, yet for indirect CP violation it yields a significantly smaller sensitivity of a_{cp}^{ind}=(-0.01 +- 0.06_{stat} +- 0.05_{syst})% due to it being based on longer decay times. New Physics models (NP) like Little Higgs Models with T-Parity (LHT) can produce an indirect CP asymmetry up to 1%; CDF's findings thus cover the upper range of realistic NP predictions ~ 0.1 - 1%. One hopes that LHCb and a Super-Flavour Factory will probe the lower range down to ~0.01%. Such non-ad-hoc NP like LHT cannot enhance direct CP violation significantly over the SM level in D^0 \to \pi^+\pi^-, K^+K^- and D^{\pm} \to \pi^{\pm}K^+K^- transitions, but others might well do so.Comment: 11 pages, 1 figure. V2 has minor corrections and corresponds to the published versio

Investigating the impact of changes in iteration-likelihoods on design process performance

Research on changes in design has mainly focused on the product domain, which is the manifestation of the design process. This article investigates changes in the process domain, which describes the execution of coordinated and concurrent design activities through interdisciplinary teams. More specifically, this article focuses on changes in the iterative behavior of activities as one of the key levers determining the performance of complex concurrent design processes. In activity network–based models of design processes, the occurrence of such behavior is often expressed probabilistically through iteration-likelihoods. First, the impact of iteration-likelihood changes on the effort and duration of both individual activities and the overall design process is examined through stochastic analysis. Consequently, a method for the investigation of such changes is developed, which grounds on an experimental approach using Monte Carlo simulation of activity network–based process models. The method is applied to the design process of a high-speed machining device for the manufacturing of planetary-ball-bearing housings. This analysis results in a two-dimensional criticality ranking of potential iteration-likelihood changes and in the identification of the most affected individual activities. The article concludes with managerial implications for process planning and improvement and discusses which design activities need to be targeted by project management to prevent and react to critical iteration-likelihood changes. This is the author accepted manuscript. The final version is available from SAGE via http://dx.doi.org/10.1177/1063293X1558820

Sudden Unexpected Natural Death in the Youth; an Iranian Single Center Investigation

Background: Sudden unexpected natural death (SUND) has not been studied in Iran. Herein we investigated its main causes in our country.Methods: Records of 80 cases registered to a single referral center were investigated to determine the distribution of sex, age, and etiology of death.Results: Fifty eight (72.5%), 6 (7.5%), 6 (7.5%) and 4 (5%) of our cases have died due to various types of heart diseases, cerebral events, pulmonary emboli and gastrointestinal bleeding (GIB), respectively. Moreover, men are victims of SUND more that women (83.7% vs.16.3%, respectively).Conclusion: Policies should be planned by the governments to prevent youth mortality in societies. These attempts should especially target ischemic heart disease

Characterization of Faecal Enterococci from Wild Birds in Turkey and Its Importance in Antimicrobial Resistance

ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗThis research aimed to investigate the diversity of faecal enterococci isolated from wild birds, to detecttheir antibiotic resistance patterns and to determine their distribution of genes related to vancomycin resistance. Additionally, to investigate their virulence factors that are important in the development of the disease. One hundred seven cloacal/rectal samples were inoculated onto Enterococcus Agar, and presumptive colonies were identified and confirmed by PCR. Multiplex PCR assays were used to screen vanA, vanB, vanC1 and vanC2/3. The virulence-related genes; ace, gelE, efa and agg were determined by PCR. Among the 103 enterococci, 62 E.faecalis, 23 E.faecium 3 E.gallinarum, 2 E.durans, 1 E.casseliflavus and 12 Enterococcus spp. were identified. Of the 103 enterococci, 26 were found to be resistant against to three or more antibiotics. The highest percentages were detected for chloramphenicol (52%), tetracycline (33%) and erythromycin (30%). Two E.gallinarum isolates were harboring three virulence factors, and one isolate was carrying a single virulence factor. There is no virulence factor in the E.casseliflavus isolate. Also, vanA and vanB genes were not found. Forty-two of 103 enterococci were harboring virulence factors, more frequently in E.faecalis. Forty-two enterococci carried efa A, 31 isolates carried gel E, and ace was found in 18 isolates. Virulence gene agg was not detected. When the results of the study were evaluated in general, multiple drug resistance was described as 25%. Considering the risk of polluting the water resources of wild animals, it is suggested that the continuity of this type of epidemiological study in wildlife animals is necessary. In conclusion, the wild birds may act as substantial reservoirs carrying antimicrobial resistance among enterococci and estimate the potential risk for man, pets and farm animals