Code smells are characteristics of the software that indicate a code or design problem which can make software hard to understand, evolve, and maintain. The code smell detection tools proposed in the literature produce different results, as smells are informally defined or are subjective in nature. To address the issue of tool subjectivity, machine learning techniques have been proposed which can learn and distinguish the characteristics of smelly and non-smelly source code elements (classes or methods). However, the existing machine learning techniques can only detect a single type of smell in the code element which does not correspond to a real world scenario. In this paper, we have used multilabel classification methods to detect whether the given code element is affected with multiple smells or not. We have considered two code smell datasets for this work and converted them into a multilabel dataset.In our experimentation, Two multilabel methods performed on the converted dataset which demonstrates good performances in the 10-fold cross-validation, using ten repetitions.

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In mobile database environments, multiple users may access similar data items irrespective of their physical location leading to concurrent access anomalies. As disconnections and mobility are the common characteristics in mobile environment, performing concurrent access to a particular data item leads to inconsistency. Most of the approaches use locking mechanisms to achieve concurrency control. However this leads to increase in blocking and abort rate. In this paper an optimistic concurrency control strategy using on-demand multicasting is proposed for mobile database environments which guarantees consistency and introduces application-specific conflict detection and resolution strategies. The simulation results specify increase in system throughput by reducing the transaction abort rates as compared to the other optimistic strategies proposed in literature.

The inherent limitations of mobile database systems makes concurrency control an important problem. Several pessimistic and optimistic strategies for achieving concurrency control in mobile database systems are presented in literature. The pessimistic strategies achieve concurrency however they face the problem of blocking, whereas the optimistic strategies may not always keep the data consistent. The conflict resolution strategies may result in starvation of some of the mobile requests. This paper presents a hybrid concurrency control strategy by using the good properties of both pessimistic and optimistic approaches. The results specify that the proposed strategy performs better as compared to both pessimistic and optimistic strategies and reduces the starvation of transaction requests of various mobile devices.