• Journal of Internet Computing and Services
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• v.15 no.3
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• pp.1-10
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• 2014

The cloud computing paradigm introduced pay-per-use models in which IT services can be created and scaled on-demand. However, service providers are still concerned about the constraints imposed by their physical infrastructures. In order to keep the required QoS and achieve the goal of upholding the SLA, virtualized resources must be efficiently consolidated to maximize system throughput while keeping energy consumption at a minimum. Using ANN, we propose a predictive SLA-aware approach for consolidating virtualized resources in a cloud environment. To maintain the QoS and to establish an optimal trade-off between performance and energy efficiency, the server's utilization threshold dynamically adapts to the physical machine's resource consumption. Furthermore, resource-intensive VMs are prevented from getting underprovisioned by assigning them to hosts that are both capable and reputable. To verify the performance of our proposed approach, we compare it with non-optimized conventional approaches as well as with other previously proposed techniques in a heterogeneous cloud environment setup.

• Journal of Internet Computing and Services
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• v.1 no.2
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• pp.11-18
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• 2000

In this paper we present a new extensible model based upon the concept of subtransactions in real-time transaction systems. The nested transaction model originally proposed by J. Moss is extended for real-time uniprocessor transaction systems by adding explicit timing constraints. Based upon the model, an integrated concurrency control and scheduling algorithm is developed, that not only guarantees timing constraints of a set of real-time transactions but also maintains consistency of the database. The algorithm is based on the priority ceiling protocol of Sha et al. We prove that the Real-Time Nested Priority Ceiling Protocol prevents unbounded blocking and deadlock, and maintains the serializability of a set of real-time transactions. We use the upper bound on the duration that a transaction can be blocked to show that it is possible to analyze the schedulability of a transaction set using rate-monotonic priority assignment. This work is viewed as a step toward multiprocessor and distributed real-time nested transaction systems. Also, it is possible to be extended to include the real-time multimedia transactions in the emerging web-based database application areas.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.12
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• pp.537-546
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• 2014

The purpose of this study is to develope an algorithm which generates trip plans based on rating points of travel app users and travel experts to help potential travellers experience their desired destinations in advance. This algorithm uses the above rating points and the gradually created hierarchy to generate the most preferred and efficient trip courses. Users can go through video clips or panoramic VR videos of the actual destinations from their trip plans generated by the algorithm which may add excitement to their actual trips. With our heuristic methods, the more users input their ratings, the better trip plans can be generated. This algorithm has been tested on android OS and proven efficient in generating trip plans. This research introduces a way to experience travel destinations with panoramic VR video and proposes the algorithm which generates trip plans based on users' ratings. It is expected to be useful for travellers' trip planning and to contribute growth in the travel market.

• The Transactions of the Korea Information Processing Society
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• v.6 no.4
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• pp.959-968
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• 1999

several papers have reported that parallel heuristics or hybrid approaches combining several heuristics can get better results. However, the parallelization and hybridization of any search methods on the single CPU type computer need enormous computation time. that case, we need more elegant combination method. For this purpose, we propose Fast Model of Parallel Heuristics(FMPH). FMPH is based on the island model of parallel genetic algorithms and takes local search to the elite solution obtained form each island(sub group). In this paper we introduce how can we adapt FMPH to the job-shop scheduling problem notorious as the most difficult NP-hard problem and report the excellent results of several famous benchmark problems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.8
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• pp.1466-1477
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• 2016

Public key infrastructure(PKI), principle technology of the certificate, is a security technology providing functions such as identification, non-repudiation, and anti-forgery of electronic documents on the Internet. Our government and financial organizations use PKI authentication using ActiveX to prevent security accident on the Internet service. However, like ActiveX, plug-in technology is vulnerable to security and inconvenience since it is only serviceable to certain browser. Therefore, the research on HTML5 authentication system has been conducted actively. Recently, domestic bank introduced PKI authentication complying with web standard for the first time. However, it still has inconvenience to register a certification on each website because of same origin policy of web storage. This paper proposes the certificate based SSO protocol that complying with web standard to provide user authentication using certificate on several sites by going around same origin policy and its security proof.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.871-874
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• 2007

Stream data need a efficient data management with high reliability and real time processing. The characteristics of these data are a large volume, a short report interval and asynchronous report time. The typical queries of these systems consist of the current query to search the latest signal value, the snapshot query to search the signal value of a past time, the historical query to search the signal value of a past time to current. This paper proposes the efficient method to manage the above signals by using a file structured database in QNX operating systems. The query model to accommodate various query for stream data is proposed. The proposed methods are applied to reactive protection system to verify their usefulness. The COM(Cabinet Operator Module) based on the QNX employs file database that adopts a delta version and a buffering method for the resource limit of a small storage and a low computing power.

• Journal of KIISE:Software and Applications
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• v.31 no.10
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• pp.1286-1303
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• 2004

Component-based Development is gaining a wide acceptance as an economical software development paradigm to develop applications by utilizing reusable software components. Well-defined interface manages coupling and cohesion between components, minimizes the effect on the user in case of component evolvement, and enhances reusability, extendibility and maintainability. Therefore, study on systematic development process and design guidelines for component interface has been required since the component has been introduced. In this paper, we propose three types of interfaces based on software architecture layers and functionality types； Provided Interface which provides functionality of a component, Required Interface which specifies required functionality that is provided by other components, and Customize Interface which tailors the component to customer's requirement. In addition, we suggest design criteria for well-designed interface, and systematic process and instructions for designing interface. We firstly cluster operations extracted from use case model and class model to identify Provided interfaces, and design Customize interfaces based on artifacts for variability. We also specify Required interfaces by identifying dependency among interfaces. Proposed interface design method provides traceability, throughout the component interface design. And furthermore, proposed guidelines support practical design for high quality component based on a case study.

• Journal of Internet Computing and Services
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• v.9 no.6
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• pp.89-97
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• 2008

Recently, many organizations such as companies or institutions have demanded induction of very large-scale workflow management system in order to process a large number of business-instances. Workflow-related vendors have focused on physical extension of workflow engines based on device-level clustering, so as to provide very large-scale workflow services. Performance improvement of workflow engine by simple physical-connection among computer systems which don't consider logical-level software architecture lead to wastes of time and cost for construction of very large-scale workflow service environment. In this paper, we propose methodology for performance improvement based on logical software architectures of workflow engine. We also evaluate scalable performance between workflow engines using the activity instance based architecture and workcase based architecture, our proposed architecture. Through analysis of this test's result, we can observe that software architectures to be applied on a workflow engine have an effect on scalable performance.

• Journal of Korean Society of Transportation
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• v.21 no.2
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• pp.63-70
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• 2003

Real-time information on vehicle queue at intersections is essential for optimal traffic signal control, which is substantial part of Intelligent Transport Systems (ITS). Computer vision is also potentially an important element in the foundation of integrated traffic surveillance and control systems. The objective of this research is to propose a method for detecting an exact queue lengths at signalized intersections using image processing techniques and a neural network model Fuzzy ARTMAP, which is a supervised and self-organizing system and claimed to be more powerful than many expert systems, genetic algorithms. and other neural network models like Backpropagation, is used for recognizing different patterns that come from complicated real scenes of a car park. The experiments have been done with the traffic scene images at intersections and the results show that the method proposed in the paper could be efficient for the noise, shadow, partial occlusion and perspective problems which are inevitable in the real world images.

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.8
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• pp.203-210
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• 2018

Mobile traffic is increasing consistently, and mobile carriers are becoming more and more hard to meet this ever-increasing mobile traffic demand by means of additional installation of base stations. To overcome this problem, heterogeneous networks, which can reuse space and frequency by installing small cells such as femto cells in existing macro cells, were introduced. However, existing macro cell users are difficult to increase the spectral efficiency without the cooperation of femto owners. Femto owners are also reluctant to accommodate other mobile stations in their femto stations without proper incentive. In this paper, a method of obtaining the optimal incentive is proposed, which adopts a utility function based on the logarithm of throughput of mobile stations, and the incentive is calculated to maximize the utility of the entire network.