• Journal of the Korea Society of Computer and Information
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• v.17 no.2
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• pp.1-11
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• 2012

Recently, we have seen several implementations that virtualize the ARM architecture. Since the current ARM architecture is not possible to be virtualized using the traditional technique called "trap-and-emulation", we usually detect all virtualization sensitive instructions during the run-time of a guest kernel and emulate them virtually rather than executing them directly. The emulation for virtualization is usually implemented either by binary translation or interpretation. Our research is about how to improve the performance of emulation for virtualization based on interpretation. The interpretation usually requires a few steps: instruction fetching, instruction decoding and instruction executing. In this paper, we propose a method that decodes all virtualization sensitive instructions during the compilation time of a guest kernel and reduces the time required for interpretation during the run time of the guest kernel. Our method provides both implementation simplicity and performance improvement of emulation for virtualization based on interpretation.

• Journal of KIISE:Software and Applications
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• v.30 no.11
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• pp.1044-1053
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• 2003

A virtual science experience space(VSES) using virtual reality technology including haptic device is proposed to overcome limits which the existing science education has and to improve the effect of it. Four example scientific worlds such as Micro World, Friction World, Electromechanical World and Macro World are demonstrated by the developed VSES. Van der Waals forces in Micro World and Stick-Slip friction in Friction World, the principle of induction motor and power generator in Electromechanical World and Coriolis acceleration that is brought about by relative motion on the rotating coordinate are modeled mathematically based on physical principles. Emulation methods for haptic interface are suggested. The proposed VSES consists of haptic device, HMD or Crystal Eyes and a digital computer with stereoscopic graphics and GUI. The proposed system is believed to increase the realism and immersion for user.

• Smart Media Journal
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• v.3 no.4
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• pp.9-15
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• 2014

A virtual platform models a processor core and the peripheral devices constituting the SoC in software. Major companies utilize a variety of platforms for product development with optimal SW+SoC integrated system architecture design and IP reuse based Top-Down design flow using a virtual platform. In this paper, we propose a virtual platform based on OpenRISC, an open source RISC based core. The proposed virtual platform supports high speed emulation of approximately 20 MIPS using DBT (Dynamic Binary Translation).

• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.6
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• pp.385-393
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• 2017

As the use of mobile devices such as smartphones increases, there is growing interest on the benefits of virtualization in embedded systems. Full virtualization has the advantage of running the guest virtual machine without modifying the guest operating system. However, full virtualization suffers slow execution speed due to the cost of context switching between the virtual machines and the virtual machine monitor. In this paper, we propose a translated block and context switching optimization to improve the guest execution speed in the embedded system. As a result, the improved dynamic binary translator is up to 5.95 times faster than the native execution. Performance degradation is less than that of the other virtualization system.

• KIISE Transactions on Computing Practices
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• v.21 no.7
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• pp.506-511
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• 2015

IOV is a technology that supports one or more virtual desktops, and can share a single physical device. In general, the virtual desktop uses the virtual IO devices which are provided by virtualization SW, using SW emulation technology. Virtual desktops that use the IO devices based on SW emulation have a problem in which service quality and performance are declining. Also, they cannot support the high-end application operations such as 3D-based CAD and game applications. In this paper, we propose a physical network separation system using Virtual Desktop Service based on HW direct assignments to overcome these problems. The proposed system provides independent desktops that are used to access the intranet or internet using server virtualization technology in a physical desktop computer for the user. In addition, this system can also support a network separation without network performance degradation caused by inspection of the network packet for logical network separations and additional installations of the desktop for physical network separations.

• The KIPS Transactions:PartC
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• v.19C no.2
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• pp.127-134
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• 2012

In this paper, we propose a mobility management scheme which has a simple IP emulation method based on virtual interface. This scheme supports prevention of service abortion resulting from RAT (Radio Access Technology) interface switching during vertical handover and provides mobility management convenience according to maintenance of consistency in simple IP mobility management scheme of 3rd generation mobile network. Through the empirical experiments of proposed method, we check out the improvement of handover performance of the proposed scheme based on vertical handover latency comparing with a non-virtual interface system.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.5
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• pp.231-236
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• 2008

This paper proposes a cost-efficient and flexible FPGA-based logic circuit emulation platform. By improving the performance and adding more features, this new platform is an enhanced version of our LAPG. It consists of an FPGA-based hardware engine and software element to drive the emulation and monitor the results. It also provides an interactive verification environment which uses an efficient communication protocol through a bi-directional serial link between the host and the FPGA board. The experimental results show that this new approach saves $55%{\sim}99%$ of communication overhead compared with other methods. According to the test results, the new LAPG is more area efficient in complex circuits with many I/O ports.

• The Magazine of the IEIE
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• v.22 no.12
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• pp.27-44
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• 1995

초고속 통신망에 근간이 되는 ATM 통신망에 SUN W/S, PC 컴퓨터들을 접속시키는 ATM Adapter Card은 하드웨어, 시스템 소프트웨어 및 응용 소프트웨어로 구성된다. 하드웨어의 구조 및 시스템 소프트웨어의 구조, 성능에 따라서 ATM Adapter Card 위에서 수행되는 응용 소프트웨어의 성능을 결정할 것이다. ATM Adapter Card는 효율적으로 Native ATM 응용 소프트웨어를 지원할 뿐 아니라, 기존의 TCP/IP 응용 소프트웨어를 수용하는 IPoverATM, LAN Emulation 기능도 지원하여야 한다. 또한 PVC(Permanent Virtual Channel), SVC(Siganlling Virtual Channel)을 위하여 ATM Forum UNI 3.1에 준한 Signalling도 필요하다. 이러한 조건들을 만족시키기위하여, 현재 개발 완료된 SUN W/S SBus용 디바이스 드라이버는 DLPI(Data Link Provider Interface), STREAM 방식으로 구현하였으며, 현재 개발 중인 PC PCI용 ATM Adapter Card의 디바이스 드라이버는 NDIS 3.0 방식으로 구현 다양한 Transport Layer를 ATM망에 수용하도록 하였다. Signalling은 Daemon Process를 이용하여 구현하였다.

• 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.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2020.11a
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• pp.151-152
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• 2020

There is a possibility of failure as a result of field application in the planning and execution process to change the operating policy for operating terminals, so a lot of time and effort are required to reduce trial and error. In the planning stage to change the terminal operation policy, simulation technology can be used to support decision making. This study introduces a case of using a virtual terminal system among simulation technologies.