• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.257-258
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• 2014

클라우드 가상화 환경에서 물리서버 노드 단위의 자원할당이 정적 로드밸런싱에 기반을 두고 있어 서비스 요청에 대한 효과적인 자원 할당의 문제가 대두되고 있다. 본 논문에서는 XenServer 기반 가상화 환경에서의 물리서버의 자원 사용량과 사용자 요청 트래픽을 모니터링하여, 동적 자원재할당하는 방안을 제시한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.270-273
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• 2015

In shipbuilding and marine industry, engineering and design software solutions have upgraded from the original 2D schematic data based CAD system to a modern 3D drawing-based system. Due to the fact that the massive amount of data usage in real time and data volumes of various engineering models including graphic data have increased, several problems such as lack of server resources and improper handling of 3D drawings have been raised. Besides, increasing the number of session connections per server can cause deterioration of server performance. Recently, increasing the yard's sophisticated design capabilities highlighted the need to develop engineering and design system which would not only overcome the network performance issues, but would provide efficient collaborative design environment. This paper presents an overview of the framework for collaborative engineering design system based on the virtual application (Citrix XenApp 6.5)and acceleration hardware technology of 3D graphics (NVIDIA GRID K2 solution).

• Journal of the Korea Society of Computer and Information
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• v.13 no.1
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• pp.55-64
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• 2008

Recently virtualization becomes one of the most popular research topics. and a lot of software products which is related to virtualization have been released accordingly. Server virtualization, which virtualize physical servers to supply many virtual servers, provides very efficient way to build network-based servers. In this paper, we design and implement virtual desktop service which is based on server virtualization. We also propose load balancing scheme for the virtual desktop service. The proposed virtual desktop service and its load balancing scheme provides a cost-effective way to build high-performance remote desktop service.

• Journal of KIISE:Computer Systems and Theory
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• v.37 no.3
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• pp.147-160
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• 2010

The system virtualization shows interest in the consolidation of servers for the efficient utilization of system resources. There are many various researches to utilize a server machine more efficiently through the system virtualization technique, and improve performance of the virtualization software. These researches have studied with the activity to control the resource allocation of virtual machines dynamically focused on CPU, or to manage resources in the cross-machine using the migration. However, the researches of the memory management have been wholly lacking. In this respect, the use of memory is limited to allocate the memory statically to virtual machine in server consolidation. Unfortunately, the static allocation of the memory causes a great quantity of the idle memory and decreases the memory utilization. The underutilization of the memory makes other side effects such as the load of other system resources or the performance degradation of services in virtual machines. In this paper, we suggest the dynamic allocation of the memory in Xen to control the memory allocation of virtual machines for the utilization without the performance degradation. Using AR model for the prediction of the memory usage and ACO (Ant Colony Optimization) algorithm for optimizing the memory utilization, the system operates more virtual machines without the performance degradation of servers. Accordingly, we have obtained 1.4 times better utilization than the static allocation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2462-2472
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• 2014

Recently, the computing paradigm has been changing and VoIP technology is being revisited to support various services. In this paper, we have designed and implemented the system of software PBX open source Asterisk, hardware platform, and mobile devices to support secured voice service based on VoIP. Specially, we designed the various platform from single board to servers based on XenServer in hardware platform. And we verified the delay test of network traffics and the secured voice communication test based on this platform.

• Smart Media Journal
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• v.6 no.3
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• pp.29-40
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• 2017

Lately weight for smartphone mounted to function for NFC is increasing, rapidly. Because of this, NFC related technology is made by many companies. We developed Gallery-Auction for security enhancements and new services of NFC-based 2 factor electronic payment system. Enhanced security features development of user authentication module through fingerprint recognition to apply FIDO authentication technology and developed electronic contract voice service of Gallery-Auction using TTS(Text to Speech). Therefore we enhanced convenient and simple authentication method and security through NFC mobile electronic payment.

• Journal of Advanced Navigation Technology
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• v.15 no.2
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• pp.313-318
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• 2011

Virtualization has recently come under the spotlight as an important emerging technology. The technology was initially focused on services rather than the effective use of the system when it was developed in the 1960s. Now, following with technological advancement, virtualization is used on servers based on x86. The biggest merit by far of this technology is economic. Virtualization enables server integration, which can cut operating expenses (including personnel expenses) since it costs less to purchase, power and maintain multiple servers if they are integrated by the virtualization technology. This study examines the trend of virtualization technology and suggests a roadmap for future server integration.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.11
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• pp.2670-2677
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• 2014

The technique of virtual machine construction using hypervisor such as Xen and KVM is mainly used for implementation of cloud computing infrastructure. This technique is efficient in allocating and managing resources compared to the existing operation methods. However it requires high resource usage when constructing virtual machines and results in wasting of resources when not using the allocated resources. Docker is a technique based on the container method to resolve such a problem. This paper shows the container method such as Docker is efficient as a web construction technique by comparing virtual machine method to container method. It is shown to be especially useful when storing data into DB or storage devices in such environments of web server or program development. In the upcoming cloud computing environment the container method such as Docker is expected to improve the resource efficiency and the convenience of management.

• Journal of KIISE:Computer Systems and Theory
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• v.37 no.1
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• pp.35-42
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• 2010

Guest operating systems running over the virtual machines share a variety of resources. Since CPU is allocated in a time division manner it consequently leads them to having the unknown physical time. It is not regarded as a serious problem in the server virtualization fields. However, it becomes critical in embedded systems because it prevents guest OS from executing real time tasks when it does not occupy CPU. In this paper we propose a hypercall to register a timer service to notify the timer request related real time. It enables hypervisor to schedule a virtual machine which has real time tasks to execute, and allows guest OS to take CPU on time to support real time. The following experiment shows its implementation on Xen-Arm and para-virtualized Linux. We also analyze the real time performance with response time of test application and frames per second of Mplayer.

• IEMEK Journal of Embedded Systems and Applications
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• v.8 no.3
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• pp.145-153
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• 2013

Virtualization technology has been applied in IA-32 based server or desktop systems. Recently it has been applied in ARM based mobile systems. Virtualization technology provides many useful features that are not possible in operating system level such as isolation, interposition, encapsulation and portability. In this research, we implement an ARM based VMM(Virtual Machine Monitor) by using the following techniques. First, we use "emulation" to virtualize the processor. Second, we use "shadow page tables" to virtualize the memory. Finally, we use a simple "pass-through I/O" to virtualize the device. Currently the VMM runs ARM Linux kernel 3.4.4 on a BeagleBoard-xM, and we evaluated the performance of the VMM using lmbench and dhrystone. The result of the evaluation shows that our VMM is slower than Xen on ARM that is implemented using paravirtualization but has good performance among the VMMs using full-virtualization.