• International Journal of Computer Science & Network Security
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• v.21 no.2
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• pp.1-8
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• 2021

Cloud computing has proven its efficiency, especially after the increasing number of cloud services offered by a wide range of cloud providers, from different domains. Despite, these cloud services are mostly heterogeneous. Consequently, and due to the rising interest of cloud consumers to adhere to a multi-cloud environment instead of being locked-in to one cloud provider, the need for semantically interconnecting different cloud services from different cloud providers is a crucial and important task to ensure. In addition, considerable research efforts proposed interoperability solutions leading to different representation models of cloud services. In this work, we present our solution to overcome this limitation, precisely in the IAAS service model. This solution is a framework permitting the semantic interoperability of different IAAS resources in a multi-cloud environment, in order to assist cloud consumers to retrieve the cloud resource that meets specific requirements.

• KIISE Transactions on Computing Practices
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• v.23 no.4
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• pp.238-243
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• 2017

This paper presents a study regarding a systemic structure that forms a link between heterogeneous terminals and the WebRTC (Web real-time communication) based video-conferencing systems. This system consists of a WebRTC-based terminal, a signal server for the relaying of the necessary signals for media negotiations, an MCU provides an interworking interface for the heterogeneous terminal, and the heterogeneous terminals that interwork with the MCU. This technology enables the interoperability between the WebRTC-based video-conferencing solutions and the legacy devices. In addition to reducing the replacement costs regarding new-technology-based solutions, the existing legacy equipment enables the use of multiparty-conference, thereby increasing the use ability of the conferencing systems.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.2
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• pp.183-194
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• 2002

The clustering environment with heterogeneous workstations provides the cost effectiveness and usability for executing applications in parallel. Load balancing is considered a necessary feature for a cluster of heterogeneous workstations to minimize the turnaround time. Previously, static load balancing that assigns a predetermined weight for the processing capability of each workstation, or dynamic approaches which execute a benchmark program to get relative processing capability of each workstation were proposed. The execution of the benchmark program, which has nothing to do with the application being executed, consumes the computation time and the overall turnaround time is delayed. In this paper, we present efficient methods for task distribution and task migration, based on the relative load index. We designed and implemented a load balancing system for the clustering environment with heterogeneous workstations. Turnaround times of our methods and the round-robin approach, as well as the load balancing method using a benchmark program, were compared. The experimental results show that our methods outperform all the other methods that we compared.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.10
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• pp.4662-4677
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• 2018

The dynamic opportunistic device-to-device (DO-D2D) network will frequently emerge in the fifth generation (5G) wireless communication due to high-density and fast-moving mobile devices. In order to improve the Quality of Experience (QoE) of users with different computing capacity devices in the DO-D2D network, in this paper, we focus on the study of how to reduce the packets retransmission delay and satisfy heterogeneous devices. To select as many devices as possible to transmit simultaneously without interference, the concurrent transmitters-selecting algorithm is firstly put forward. It jointly considers the number of packets successfully received by each device and the device's connectivity. Then, to satisfy different devices' demands while primarily ensuring the base-layer packets successfully received by all the devices, the layer-cooperation instantly decodable network coding is presented, which is used to select transmission packets combination for each transmitter. Simulation results illustrate that there is an appreciable retransmission delay gain especially in the poor channel quality network compared to the traditional base-station (BS) retransmission algorithm. In addition, our proposed algorithms perform well to satisfy the different demands of users with heterogeneous devices.

• Journal of Internet Computing and Services
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• v.2 no.3
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• pp.81-92
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• 2001

The clustering environment with heterogeneous workstations provides the cost effectiveness and usability for executing applications in parallel. The load balancing is considered as a necessary feature for the clustering of heterogeneous workstations to minimize the turnaround time. Since each workstation may have different users, groups. requests for different tasks, and different processing power, the capability of each processing unit is relative to the others' unit in the clustering environment Previous works is a static approach which assign a predetermined weight for the processing capability of each workstation or a dynamic approach which executes a benchmark program to get relative processing capability of each workstation. The execution of the benchmark program, which has nothing to do with the application being executed, consumes the computation time and the overall turnaround time is delayed. In this paper, we present an efficient task distribution method and implementation of load balancing system for the clustering environment with heterogeneous workstations. Turnaround time of the methods presented in this paper is compared with the method without load balancing as well as with the method load balancing with performance evaluation program. The experimental results show that our methods outperform all the other methods that we compared.

• The Transactions of the Korea Information Processing Society
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• v.6 no.7
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• pp.1777-1788
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• 1999

The portability of Java language makes it possible to use heterogeneous computers without re-compiling of application programs. Java applet can also be transported to other computers via Web browser. In this research, a Cooperative Web Computing Environment(CWCE) that uses idle computers on the Intranet for cooperative parallel computing work is suggested. The CWCE allows to use more than a manager computer that sends applets and manages communication between other computers. The number of manager computers can be determined according to the characteristics of computing environment and any chosen application program. It can reduce the amount of communication overhead for the application programs especially with synchronized communication. For the CWCE, a decision function to determine the managing level is provided. The CWCE turns out to be useful computing environment for the applications with less computation request ratio and multi-managing can help to reduce the communication overhead especially for the applications with a high ratio of synchronization purpose communications.

• Journal of Computing Science and Engineering
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• v.5 no.2
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• pp.141-149
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• 2011

Many distributed and heterogeneous services and devices are accessible in ubiquitous computing environment, so interoperating those services and devices is one of the key tasks in implementing ubiquitous applications. We used to use script languages in integrating such interoperating components and services. However currently available most script languages are not suitable for ubiquitous environment because there are so diverse forms of interoperation targets such as service objects, web, legacy objects and programmable devices. So it is worthwhile designing a new script language well-suited to ubiquitous environment. In this paper, we propose a new script language, called Ubiscript, for the ubiquitous environment. We develop and adopt several unique language features such as remote scope, multiple contexts, web and legacy objects, remote exception handling, etc. in Ubiscript to overcome the limitations of conventional script languages. In this paper, we also describe the implementation of Ubiscript and its runtime system. A couple of ubiquitous applications were developed in Ubiscript, and the applications are tested on the runtime system. According to our experiences and evaluation, Ubiscript turned out to have a high potential in its expression power and contribution to improving ubiquitous application developers' productivity.

• KIISE Transactions on Computing Practices
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• v.23 no.3
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• pp.165-170
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• 2017

Many studies have utilized GPGPU (General-Purpose Graphic Processing Unit) and its high computing power to compute complex tasks. The characteristics of GPGPU programs necessitate the operations of memory copy between the host and device. A high latency period can affect the performance of the program. Thus, it is required to significantly improve the performance of GPGPU programs by optimizations. By executing multiple GPGPU programs simultaneously, the latency hiding effect of memory copy is achieved by overlapping the memory copy and computing operations in GPGPU. This paper presents the results of analyzing the latency hiding effect for memory copy operations. Furthermore, we propose a performance anticipation model and an algorithm for the limitations of using pinned memory, and show that the use of the proposed algorithm results in a 41% performance increase.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.8
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• pp.773-777
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• 2008

Today's mobile devices have characteristic of random mobility in the heterogeneous networks. Thus they should have various kinds of security requirements. To satisfy these requirements, there are many researches on security and authentication for mobile devices. TCG(Trusted Computing Group) designed TPM(Trusted Platform Module) for providing privacy and authentication to users. Also TCG suggest a protocol, called DAA(Direct Anonymous Attestation) which uses zero knowledge proof theory. In this paper, we will implement DAA protocol using Java and show the efficiency and the problems in the DAA protocol. Finally, we will suggest an efficient mobile DAA model through Java test module for the DAA protocol.

• Journal of Digital Convergence
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• v.12 no.2
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• pp.163-171
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• 2014

Cloud computing(cloud) is a good candidate for complementing weaknesses of logistics information systems(heterogeneous processes not able to be standardized, geographically scattered and seamed connectivity, etc.) and for supporting innovative activities of logistics. In this sense, we aimed to study deployment strategies of clouds specified in the logistics industry. To achieve our research goal, we reviewed up-to-date logistics clouds researches and analysis of clouds; platforms and deployment strategies for logistics. This study contributes to follow-up researches for establishing a development direction of logistics specific clouds and developing more concrete clouds for logistics.