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Hadoop uses the Hadoop distributed file system for storing big data, and uses MapReduce to process big data in cloud computing environments. Because Hadoop is optimized for large file sizes, it has difficulties processing large numbers of small files. A small file can be defined as any file that is significantly smaller than the Hadoop block size, which is typically set to 64 MB. Hadoop is optimized to store data in relatively large files, and thus suffers from name node memory insufficiency and increased scheduling and processing time when processing large numbers of small files. This study proposes a performance improvement method for MapReduce processing, which integrates the CombineFileInputFormat method and the reuse feature of the Java Virtual Machine (JVM). Existing methods create a mapper for every small file. Unlike these methods, the proposed method reduces the number of created mappers by processing large numbers of files that are combined by a single split using CombineFileInputFormat. Moreover, to improve MapReduce processing performance, the proposed method reduces JVM creation time by reusing a single JVM to run multiple mappers (rather than creating a JVM for every mapper). [ABSTRACT FROM AUTHOR]

Many researches have been converging on automatic text summarization as increasing of text documents due to the expansion of information diffusion constantly. The objective of this proposal is to achieve the most reliable and substantial context or most relevant brief summary of the text in extractive manner. The extractive text summarization produces the short summary of a certain text which contains the most important information of original text by extracting the set of sentences from the original document. This paper proposes an improved extractive text summarization method for documents by enhancing the conventional lexical chain method to produce better relevant information of the text using three distinct features or characteristics of keyword in a text. The keyword of the document is labeled using our previous work, transition probability distribution generator model which can learn the characteristics of the keyword in a document, and generates their probability distribution upon each feature. [ABSTRACT FROM AUTHOR]

In this paper, we present the framework of a channel allocation (CA) and power control (PC) schemes for the minimization of interference in cross-tier 3GPP LTE networks that aim to support internet of multimedia things. Channel allocation scheme based on an interference graph preserving the minimum number of interfered MUEs by femtocells (IG-MIM) is proposed to mitigate interference amongst femtocells, and a game theory based power control algorithm is also proposed to reduce interference to surrounding macrocell users (MUEs). The proposed IG-MIM scheme constructs the interference graph based on a predefined threshold and allocates the subchannels to the femtocells that maintain the smallest number of interfered MUEs. For the power control, we design a payoff function based on the rewards from the achieved data rates and the penalties from the interference in regards to its adjacent femtocells. The simulation results show that the IG-MIM channel allocation significantly improves the SINR performance for the femtocell users (FUEs) being served; the game theory based power control decreases the power requirements of a femtocell and alleviates the interference to the MUEs. [ABSTRACT FROM AUTHOR]

In the field of 'U-Healthcare Service', many studies have been actively conducted to develop 'smart device'-based healthcare applications that enable healthcare providers and patients to be better served through interoperations among various kinds of sensors and wireless network interfaces. In particular, contemporary intelligent healthcare services not only recognize users' context information through smart devices, computers, and so forth, but also acquire information from heterogeneous sensors to achieve context-aware inference services. Among such information, the weather information is tightly related to diseases such as asthma and allergies. Therefore, there is a high demand for research to utilize the weather information for healthcare services. In this paper, we propose a context inference-based intelligent healthcare service that exploits both the weather conditions information and the diverse healthcare ontologies available on the Internet. The proposed service aims at modeling a context ontology in users' healthcare service environment and defining the inference rules, thereby accomplishing a satisfactory real-time healthcare service. [ABSTRACT FROM AUTHOR]

Cloud computing is a more advanced technology for distributed processing, e.g., a thin client and grid computing, which is implemented by means of virtualization technology for servers and storages, and advanced network functionalities. However, this technology has certain disadvantages such as monotonous routing for attacks, easy attack method, and tools. This means that all network resources and operations are blocked all at once in the worst case. Various studies such as pattern analyses and network-based access control for infringement response based on Infrastructure as a Service, Platform as a Service and Software as a Service in cloud computing services have therefore been recently conducted. This study proposes a method of integration between HTTP GET flooding among Distributed Denial-of-Service attacks and MapReduce processing for fast attack detection in a cloud computing environment. In addition, experiments on the processing time were conducted to compare the performance with a pattern detection of the attack features using Snort detection based on HTTP packet patterns and log data from a Web server. The experimental results show that the proposed method is better than Snort detection because the processing time of the former is shorter with increasing congestion. [ABSTRACT FROM AUTHOR]

There are many security issues in cloud computing service environments, including virtualization, distributed big-data processing, serviceability, traffic management, application security, access control, authentication, and cryptography, among others. In particular, data access using various resources requires an authentication and access control model for integrated management and control in cloud computing environments. Cloud computing services are differentiated according to security policies because of differences in the permitted access right between service providers and users. RBAC (Role-based access control) and C-RBAC (Context-aware RBAC) models do not suggest effective and practical solutions for managers and users based on dynamic access control methods, suggesting a need for a new model of dynamic access control that can address the limitations of cloud computing characteristics. This paper proposes Onto-ACM (ontology-based access control model), a semantic analysis model that can address the difference in the permitted access control between service providers and users. The proposed model is a model of intelligent context-aware access for proactively applying the access level of resource access based on ontology reasoning and semantic analysis method. [ABSTRACT FROM AUTHOR]

The importance of research on knowledge management is growing due to recent issues on Big Data. One of the most fundamental steps in knowledge management is the extraction of terminologies. Terms are often expressed in various forms and the variations often play a negative role, becoming an obstacle which causes knowledge systems to extract unnecessary ones. To solve the problem, we propose a method of term normalization which finds a normalized form (original and standard form defined in dictionaries) of variant terms. The method employs two characteristics of terms: appearance similarity measuring how similar terms are, context similarity measuring how many clue words they share. Through experiment, we show its positive influence of both similarities in term normalization. [ABSTRACT FROM AUTHOR]

A unified semantic visual data-modeling framework is presented in the paper. In the proposed model, an extended conceptual graph is proposed as an annotation mechanism of a user's perceptual understanding of video objects, activities, and events. A precise definition of the term “domain knowledge” in visual information processing is presented. A conceptual structure, associated terms, visual feature extraction methods, and a set of constrains in feature extraction are considered as domain information. The proposed visual data model has six different abstraction layers. A higher level is more abstracted and more semantically summarized. A polygon-based bounding volume is used in video object approximation in space and time. We use a bounding volume in motion trajectory representation, rather than motion vectors. This model allows simultaneous access of both temporal and spatial information. The proposed model may be used as a referencing framework for various visual information management systems' developments. [ABSTRACT FROM AUTHOR]