Design of nearest neighbor classifiers: multi-objective approach

AbstractThe goal of designing optimal nearest neighbor classifiers is to maximize classification accuracy while minimizing the sizes of both reference and feature sets. A usual way is to adaptively weight the three objectives as an objective function and then use a single-objective optimization method for achieving this goal. This paper proposes a multi-objective approach to cope with the weight tuning problem for practitioners. A novel intelligent multi-objective evolutionary algorithm IMOEA is utilized to simultaneously edit compact reference and feature sets for nearest neighbor classification. Three comparison studies are designed to evaluate performance of the proposed approach. It is shown empirically that the IMOEA-designed classifiers have high classification accuracy and small sizes of reference and feature sets. Moreover, IMOEA can provide a set of good solutions for practitioners to choose from in a single run. The simulation results indicate that the IMOEA-based approach is an expedient method to design nearest neighbor classifiers, compared with an existing single-objective approach

Optical transitions between Landau levels: AA-stacked bilayer graphene

The low-frequency optical excitations of AA-stacked bilayer graphene are investigated by the tight-binding model. Two groups of asymmetric LLs lead to two kinds of absorption peaks resulting from only intragroup excitations. Each absorption peak obeys a single selection rule similar to that of monolayer graphene. The excitation channel of each peak is changed as the field strength approaches a critical strength. This alteration of the excitation channel is strongly related to the setting of the Fermi level. The peculiar optical properties can be attributed to the characteristics of the LL wave functions of the two LL groups. A detailed comparison of optical properties between AA-stacked and AB-stacked bilayer graphenes is also offered. The compared results demonstrate that the optical properties are strongly dominated by the stacking symmetry. Furthermore, the presented results may be used to discriminate AABG from MG, which can be hardly done by STM

Plant-Microbe Ecology: Interactions of Plants and Symbiotic Microbial Communities

Plant community dynamics are driven by the microbial mediation of soil resource partitioning and sharing by the inhibition of other host symbionts or sharing the broadly specific symbiotic fungi. The plant phenotype and ecology can be affected by the impact of the symbiotic microbes on the environment and competition for soil resources

Retroperitoneal Metastatic Adenocarcinoma Complicated with Necrotizing Fasciitis of the Thigh in a Patient with Advanced Rectal Colon Cancer

Background: Necrotizing fasciitis of the thigh due to colon cancer has not been previously reported, especially during radiotherapy. Case Presentation: A 73-year-old woman admitted to our hospital was diagnosed with sigmoid colon cancer that had spread to the left psoas muscle; radiotherapy was performed. Three months after the initiation of radiotherapy, the patient developed gait disturbance, poor appetite and high fever and was therefore admitted to the emergency department of our hospital. Blood examination revealed generalized inflammation with a high white blood cell count and C-reactive protein level. Computed tomography of the abdomen revealed fluid and gas tracking from the retroperitoneum into the intramuscular plane of the grossly enlarged right thigh. Consequently, emergent debridement was not performed and conservative therapy was done. The patient died. Conclusion: Necrotizing fasciitis of the thigh due to the spread of rectal colon cancer is unusual, but this fatal complication should be considered during radiotherapy in patients with unresectable colorectal cancer