• The KIPS Transactions:PartC
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• v.12C no.1 s.97
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• pp.45-52
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• 2005

A damage scale of information property has been increasing rapidly by various illegal actions of information systems, which result from dysfunction of a knowledge society. Reinforcement in criminal investigation requests of network security has accelerated research and development of Intrusion Detection Systems(IDSs), which report intrusion-detection about these illegal actions. Due to limited designs of early IDSs, it is hard for the IDSs to cope with tricks to go around IDS as well as false-positive and false-negative trials in various network environments. In this paper, we showed that this kind of problems can be solved by using a Virtual Protocol Stack(VPS) that possesses automatic learning ability through an optimum-adaptive mobile code. Therefore, the enhanced IDS adapts dynamically to various network environments in consideration of monitored and self-learned network status. Moreover, it is shown that Insertion/Evasion attacks can be actively detected. Finally, we discussed that this method can be expanded to an intrusion detection technique that possesses adaptability in the various mixed network environments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.6
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• pp.1869-1880
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• 2014

Wireless communication is one of most active areas in modern communication researches, QoS (Quality of Service) assurance is very important for wireless communication systems design, especially for applications such as streaming video etc., which requires strict QoS assurance. The modern wireless networks multi-layer protocol stack structure results in QoS metrics layered and acting in cascade and QoS metrics vertical mapping between protocol layers. Based on virtual buffer between protocol layers and queuing technology, a unified layered QoS mapping framework is proposed in this paper, in which we first propose virtual queue concept, give a novelty united neighboring protocol layers QoS metric mapping framework, and analysis method based on dicerete-time Markov chain, and numerical results show that our proposed framework represents a significant improvement over previous model.

• Journal of Computing Science and Engineering
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• v.7 no.3
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• pp.198-203
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• 2013

In this paper, we focus on a novel Internet architecture, based on the urbanization of virtual machines. In this approach, virtual networks are built linking specific virtual elements (router, switch, firewall, box, access point, etc.). A virtual network represents a network with an independent protocol stack that shares resources from the underlying network infrastructure. Virtualization divides a real computational environment into virtual computational environments that are isolated from each other, and interact with the upper computational layer, as would be expected from a real, non-virtualized environment. Metamorphic networks enhance several concepts related to future networks, and mainly the urbanization of virtual machines. We present this new paradigm, and the methodology, based on the worldwide metamorphic network platform "M-Net". The metamorphic approach could solve many complex problems, especially related to Cloud computing services.

• IEMEK Journal of Embedded Systems and Applications
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• v.5 no.4
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• pp.175-184
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• 2010

This paper designs a virtual USB drive for mobile devices which gives an illusion of a traditional USB flash memory drive and provides capacity-free storage space over IP network. The virtual USB drive operating with a S3C2410 hardware platform and embedded linux consists of USB device driver, an iSCSI-enabled network stack, and a seamless USB/iSCSI tunneling module. For performance enhancement, it additionally provides a kernel-level seamless USB/iSCSI tunneling module and data sharing with symbol references among kernel modules. Experiments reveal that the kernel-level implementation can improve the I/O performance up to 8 percentage, as compared with the user-level implementation.

• KIISE Transactions on Computing Practices
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• v.24 no.3
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• pp.129-137
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• 2018

NVMe(Non-Volatile Memory Express) SSD(Solid State Drive) is a high-performance storage that makes use of flash memory as a storage cell, PCIe as an interface and NVMe as a protocol on the interface. It supports multiple I/O queues which makes it feasible to process parallel-I/Os on multi-core environments and to provide higher bandwidth than SATA SSDs. Hence, NVMe SSD is considered as a next generation-storage for data-center and cloud computing system. However, in the virtualization system, the performance of NVMe SSD is not fully utilized due to the bottleneck of the software I/O stack. Especially, when it uses I/O stack of the hypervisor or the host operating system like Xen and KVM, I/O performance degrades seriously due to doubled-I/O stack between host and virtual machine. In this paper, we propose a new I/O engine, called Direct-AIO (Direct-Asynchronous I/O) engine, that can access NVMe SSD directly for I/O performance improvements on QEMU emulator. We develop our proposed I/O engine and analyze I/O performance differences between the existed I/O engine and Direct-AIO engine.

• The KIPS Transactions:PartA
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• v.13A no.7 s.104
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• pp.589-598
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• 2006

In this paper, we describe the development and optimization of an embedded Biuetooth solution on an SoC platform for real-time audio streaming over a Bluetooth wireless link. The solution includes embedded Bluetooth protocol stack and profile simplemented on a virtual operating system for portability, and other optimization techniques to fully exploit the benefits of multimedia-oriented SoC. The optimization techniques implemented in this paper are memory access minimization by using on-chip scratch pad memory, codec library optimization with DSP and parallel memory access instruction set, and dynamic audio quality adjustment regarding current wireless link status. Experimental results show that the optimized solution presented in this paper can support high-qualify audio streaming without the support of external memory.

• Journal of Information Technology Services
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• v.8 no.1
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• pp.193-202
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• 2009

Cloud computing emerges as a new computing paradigm which targets reliable and customizable services. The term builds on decades of research in virtual machine, distributed and parallel computing, utility computing, and more recently networking, web service, and software as a service. In this paper, we provide a seamless connection migration of web services. This is useful for cloud computing environment in which many client terminals have mobility. With the wireless internet facility, those mobile users can move place to place during internet communication. Therefore, we provide solutions to the two major problems in current virtualization based migration: communication failure problems and connection re-establishment. Communication channel flushing by zero window notification helps to resolve the communication failure problems and TCP port inheritance prevents connection re-establishment errors during socket reconstruction. Thus, our web service migration facility is now able to preserve open network connections, and even for server sockets. This is a highly transparent approach, in that we did not Introduce additional messages for channel flushing and did not make any modification to the TCP protocol stack. Experimental results show that the overhead due to connection migration of web services is almost negligible when compared with time to take the conventional web service migration.