• KIISE Transactions on Computing Practices
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• v.23 no.4
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• pp.199-209
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• 2017

Recently, there has been growing interest in workload consolidation via virtualization for real-time systems. Meanwhile, due to virtualization, additional overhead from intervention of hypervisor increases the execution time of applications running on virtual machine. The increase in execution time decreases the performance of workloads on virtual machines, thus satisfying real-time requirements are not easy. To resolve the problem, we designed and implemented a hypervisor (the K-Hypervisor) that allows programs on virtual machines to access the physical resources, without intervention of the hypervisor. Experimental results show that programs running on K-Hypervisor increase their execution time by about 3% on an average, compared to the native environment. Moreover, it is suitable for real-time workload execution because of its uniform performance degradation, regardless of the resources accessed from tasks, and the frequency it is accessed.

• Journal of the Korea Society of Computer and Information
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• v.22 no.5
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• pp.11-19
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• 2017

In this paper, we propose a hypervisor for embedded systems based on ARM microprocessor. The proposed hypervisor makes it possible to run several real-time kernels concurrently on a single embedded system by virtualizing its microprocessor. With assistance of MMU, it supports virtual memory which enables each guest operating system has its own address space. Exploiting the fact that most embedded systems use memory-mapped I/O device, it provides a mechanism to distribute an external interrupt to virtual machines properly. It also achieves load balancing through live migration which moves a running virtual machine to other embedded system. Unlike other para-virtualization techniques, minor modifications are needed to run it on the hypervisor. Extensive performance measurement studies are conducted to show that the proposed hypervisor has enough potentiality of its real-world application.

• IEMEK Journal of Embedded Systems and Applications
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• v.6 no.4
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• pp.231-241
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• 2011

Recently, system virtualization has been applied to consumer electronics (CE) such as smart mobile phones. Although multi-core processors have become a viable solution for complex applications of consumer electronics, the issue of utilizing multi-core resources in the virtualization layer has not been researched sufficiently. In this paper, we present a new hypervisor design and implementation for multi-core CE devices. We concretely describe virtualization methods for a multi-core processor and multi-core-related subsystems. We also analyze bottlenecks of network performance in a virtualization environment that supports multimedia applications and propose an efficient virtual interrupt distributor. Our new multi-core hypervisor improves network performance by 5.5 times as compared to a hypervisor without the virtual interrupt distributor.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.7
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• pp.526-534
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• 2013

With rapid rise of virtualization technology from diverse types of cloud computing service, security problems such as data safety and reliability are the issues at stake. Since damage in virtualization layer of cloud service can cause damage on all host (user) tasks, Hypervisor that provides an environment for multiple virtual operating systems can be a target of attackers. This paper propose a security structure for protecting Hypervisor from hacking and malware infection.

• Proceedings of the Korean Society of Computer Information Conference
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• 2011.01a
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• pp.29-32
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• 2011

현재 사용되고 있는 스마트폰에서는 어떤 개인정보들이 외부로 제공되고 있는지 사용자에게 알려주지 않는다. 스마트폰 개인정보 유출로 인한 피해 사례가 증가하면서, 스마트폰 사용자 프라이버시 보호의 중요성이 부각되고 있다. 본 논문에서는 스마트폰 사용자가 설정한 개인정보보호 정책을 기반으로 개인정보 접근권한을 각 어플리케이션에 부여하고, 어플리케이션이 허가되지 않은 정보에 대한 접근을 요청한 경우, 이를 차단하고 사용자에게 경고 메시지를 보여주는 방법을 제안한다. 제안하는 기법은 물리적인 하드웨어에 대한 접근을 모니터링하고 제어할 수 있는 Hypervisor 기술을 이용한다. 본 논문에서 제안하는 기법은 사용자가 허가하지 않은 개인정보의 유출을 차단할 수 있고, 프라이버시를 안전하게 보호할 수 있다.

• Journal of the Korea Society of Computer and Information
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• v.12 no.5
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• pp.103-112
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• 2007

In this paper, we implement a hypervisor that runs multiple uC/OS-II real-time kernels on one microprocessor. The hypervisor virtualizes microprocessor and memory that are main resources managed by uC/OS-II kernel. Microprocessor is virtualized by controlling interrupts that uC/OS-II real-time kernel handles and memory is virtualized by partitioning physical memory. The hypervisor consists of three components: interrupt control routines that virtualize timer interrupt and software interrupt, a startup code that initializes the hypervisor and uC/OS-II kernels, and an API that provides communication between two kernels. The original uC/OS-II kernel needs to be modified slightly in source-code level to run on the hypervisor. We performed a real-time test and an independent computation test on Jupiter 32-bit EISC microprocessor and showed that the virtualized kernels run without problem. The result of our research can reduce the hardware cost, the system space and weight, and system power consumption when the hypervisor is applied in embedded applications that require many embedded microprocessors.

• KIISE Transactions on Computing Practices
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• v.22 no.2
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• pp.89-94
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• 2016

Recently, cluster computing environments have been in a process of change toward virtualized cluster environments. The change of the cluster environment has great impact on the performance of large volume distributed processing. Therefore, many domestic and international IT companies have invested heavily in research on cluster environments. In this paper, we show how the hypervisor affects the performance of distributed processing of a large volume of data. We present a performance comparison of MapReduce processing in two virtualized cluster environments, one built using the Xen hypervisor and the other built using the container-based Docker. Our results show that Docker is faster than Xen.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.201-204
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• 2013

From 2009 to the present, smart phone users has been steadily increasing. And through the use of smart phone applications, smart phone user can perform easily what they want to do whenever and wherever. However, new types of financial fraud such as phishing, pharming and smishing are appeared exploiting these advantages. Accordingly in this paper, I propose to prevent social issues like phishing, pharming and smishing for the technical way using mobile hypervisor.

• International Journal of Computer Science & Network Security
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• v.24 no.2
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• pp.67-78
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• 2024

Software-Defined Networking (SDN) is a new emerging networking paradigm that has adopted a logically centralized architecture to increase overall network performance agility and programmability. Combining network virtualization with SDN will guarantees for combined advantages of improved flexibility and network performance. Combining SDN with hypervisors divides the network physical resources into several logical transparent and isolated virtual SDN network (vSDN), where each has its virtual controller. However, SDN hypervisors bring several advantages as well as several challenges to its network operators as for the virtual appliances, their efficient placement, assurance of network performance is mandatory, and their dynamic instantiation with their migration. In this article, we provide a brief and concise review of network virtualization along with its implementation in the SDN network. SDN hypervisors types are discussed, and taxonomy is provided to demonstrate the importance of hypervisors in SDN. A comparison of SDN hypervisors is performed to elaborate on the vital hypervisor software along with their features, and different challenges are discussed faced by the SDN network. A framework is proposed to add combined functionalities of hypervisors to create a more effective and efficient virtual system. The purpose of the framework is to increase network performance through proper configuration of resources, software, control plane isolation functions with defined rules and policies.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.7-8
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• 2017

최근 ARM 프로세서의 가상화 확장 기술을 이용하는 임베디드 시스템에서 다종의 OS 작동을 지원하는 하이퍼바이저가 많이 개발되었다. 가상화 기술은 하드웨어 자원을 효과적으로 사용한다는 이점이 있지만, RTOS를 작동시킬 경우 하이퍼바이저의 오버헤드에 의해 RTOS의 성능이 저하될 수 있는 문제가 발생한다. 본 논문에서는 가상화 기술을 지원하는 ARMv7 Cortex-A15 프로세서를 탑재한 NVidia Jetson TK-1 임베디드 보드에서 RTOS가 단독으로 작동했을 때의 성능과 QPlus Hypervisor를 통해 Linux OS와 함께 RTOS가 작동했을 때의 성능을 측정하고 비교 분석 하였다.