Mobile resource management load balancing strategy

This paper is dealing with mobile resource management that distributes mobile device processes between cloud computing virtual machine and mobile device. Expectation is that mobile device user experience will increase. Load balancing is an important part of mobile resource management. In order to be able to solve load balancing issues, discussion is made how currently available methods can be adapted to our resource manager. In this article, we investigate load balancing procedures, methods and their customization, with a particular attention on mobile and cloud computing requirements. As a result, we expect that important design aspects will become apparent. Profile based load balancing method is recommended, what combines static and dynamic load balancing strategy. Using profile to identify usage scenario of mobile device can lead to increased system responsiveness, thus experience improvement

PATTERN MATCHING IN METAMODEL-BASED MODEL TRANSFORMATION SYSTEMS

The vision of the OMG´s Model-Driven Architecture (MDA) has necessitated the extensive research of model compilers, which are able to process graph-based visual models specified mainly in the Unified Modeling Language (UML). A possible mechanism for the realization of MDA model compilers can be graph rewriting-based transformation approach. Previous work has introduced the tool Visual Modeling and Transformation System, which uses graph rewriting as transformation mechanism, but the pattern language of the rewriting rules consists of UML class diagram elements instead of object diagram level patterns. This paper provides the algorithmic background for the application of these rules specified by the class diagram elements. To achieve that, it examines the allowed instantiation configuration based on the UML standard, and supplies a constructive algorithm to compute the allowed number of the objects participating in a valid instantiation of a class model. Furthermore, starting from the VF2 algorithm, the pattern matching algorithm for the left hand side of the metamodel-based rewriting rule is provided via several optimization steps examined

Performance metrics based mobile resource management

Mobile computer technology has greatly evolved in the recent years. Cloud computing is recognized to be a new area for solving performance issues. Mobile terminal can take advantage from cloud computing. To cope with these new resources and fulfill new quality and performance requirements a more sophisticated architecture and resource management is necessary. The basis of effective resource management is a precise knowledge of the hardware and software capabilities. Performance metrics serve as an input for resource management. This study will present architecture of mobile resource management using cloud resources. The main task of such resource management is to decide which application where to run; on the mobile terminal or in the cloud. This paper identifies key components of resource management, settles the tasks and relationships between them

PERFORMANCE MODELLING OF COOPERATING TASKS IN PC CLUSTERS

Although parallel processing is a promising way of increasing the performance cost efficiently, it is important to find the balance between the potential speed-up benefits and overheads due to the organization and the increased communication. Finding the optimal distribution of co-operating tasks, minimizing overheads and maximizing execution speed are often completed based on performance prediction. Complexity of prediction gradually increases with the number of links between the cooperating tasks. In this paper the efforts are focused on building up a performance model for a category of tasks running on clusters of workstations, where the result is expected at the same node the input was fed in, and a strong dependence between the partial solutions must be resolved to obtain the final result. In this domain we investigate the possibilities of prediction and minimization of execution time in the function of the cluster size. To show the utility of our model, the results are demonstrated on the common, widely used area of integer sorting. Modelling the execution time of different sorting algorithms has a strong mathematical background, which enables to easily build up formulas for the expected execution times helping to determine the optimal cluster size. As a conclusion, we show the execution times of the sorting algorithm measured on a test cluster, and compare the predicted times and the measured results

USING CONCEPT RELATIONSHIPS TO IMPROVE DOCUMENT CATEGORIZATION

In the information age we much depend on our ability to find information hidden in mostly unstructured and textual documents. This article proposes a simple method in which (as an addition to existing systems) categorization accuracy can be improved, compared to traditional techniques, without requiring any time-consuming or language-dependent computation. That result is achieved by exploiting properties observed in the entire document collection as opposed to individual documents, which may also be regarded as a construction of an approximate concept network (measuring semantic distances). These properties are sufficiently simple to avoid entailing massive computations; however, they try to capture the most fundamental relationships between words or concepts. Experiments performed on the Reuters-21578 news article collections were evaluated using a set of simple measurements estimating clustering efficiency, and in addition by Cluto, a widely used document clustering software. Results show a 5-10% improvement in clustering quality over traditional tf (term frequency) or tf x idf (term frequency-inverse document frequency) based clustering

Evaluating dynamically evolving mobile-based social networks

The increasing capabilities of mobile phones enable them to participate in different type of web-based systems. One of the most popular systems are social networks. The phonebooks of the mobile devices also represent social relationships of the owner. This can be used for discovering additional relations in social networks. Following this line of thought, mobile-based social networks can be created by enabling a synchronization mechanism between phonebooks of the users and the social network. This mechanism detects similarities between phonebook contacts and members of the network. Users can accept or ignore these similarities. After acceptance, identity links are formed. If a member changes her or his personal detail, it will be propagated automatically into the phonebooks, via identity links after considering privacy settings. Estimating the total number of these identity links is a key issue from scalability and performance point of view in such networks. We have implemented a mobile-based social network, called Phonebookmark and examined the structure of the network during a test period of the system. We have found, that the distribution of identity links of the users follows a power law. Based on this, we propose a model for estimating the total number of identity links in the dynamically evolving network. We verify the model by measurements and we also prove the accuracy of the model mathematically. For this we use the fact, that the number of identity links of each user (and thus, the value of the random variable modeling it) is bounded linearly by the number of members Nm of the network. Then we show, that the variance of the random variable is Θ(Nm3-β), where 2 0, Pr[X = x] = c∙x-β, if x ≤ Nm and Pr[X = x] = 0 otherwise. The model and the results can be used in general when the distribution shows similar behavior

Constraint validation support in visual model transformation systems

Model-Driven Architecture (MDA) standardized by OMG facilitates to separate the platform independent part and the platform specific part of a system model. Due to this separation Platform-Independent Model (PIM) can be reused across several implementation platforms of the system. Platform-Specific Model (PSM) is ideally generated automatically from PIM via model transformation steps. Because of the appearance of high level languages, object-oriented technologies and CASE tools, metamodeling becomes more and more important. Metamodeling is one of the most central techniques both in design of visual languages, and reuse existing domains by extending the metamodel level. The creation of model compliers on a metamodeling basis is illustrated by a software package called Visual Modeling and Transformation System (VMTS), which is an n-layer multipurpose modeling and metamodel-based transformation system. VMTS is able to realize an MDA model compiler. This paper (i) addresses the relationship between the constraints enlisted in metamodel-based rewriting rules and the pre- and postconditions, (ii) it introduces the concepts of general validation, general preservation and general guarantee, which facilitate that if a transformation step is specified adequately with the help of constraints, and the step has been executed successfully for the input model, then the generated output model is in accordance with the expected result, which is described by the transformation step refined with the constraints. An illustrative case study based on constraint specification in rewriting rules is also provided

Novel Techniques For Model-Code Synchronization

The orientation of the current software development practice requires efficient model-based iterative solutions. The high costs of maintenance and evolution during the life cycle of the software can be reduced by using tool-aided iterative development. This paper presents how model-based iterative software development can be supported through efficient model-code change propagation. The presented approach facilitates bi-directional synchronization between the modified source code and the refined initial models. The backgrounds of the synchronization technique are three-way abstract syntax tree (AST) differencing and merging. The AST-based solution enables syntactically correct merge operations. OMG's Model-Driven Architecture describes a proposal for platform-specific model creation and source code generation. We extend this vision with the synchronization feature to assist the iterative development. Furthermore, a case study is also provided

A Model Transformation for Automated Concrete Syntax Definitions of Metamodeled Visual Languages

Metamodeling techniques are popular in describing the rules of special domains, but these techniques do not support defining presentation for these domains , namely the concrete syntax. The aim of our research is to provide a method to create the concrete syntax for metamodeling systems in a flexible, efficient way. Several domain-specific languages have been created that support defining the concrete syntax, i.e. the visualization. The main concern of this paper is to present a model transformation method that processes our presentation definitions and transforms them automatically into source code. The source code implements a plug-in capable of editing the models. A termination analysis for the presented method is also provided