• The KIPS Transactions:PartA
• /
• v.8A no.4
• /
• pp.375-384
• /
• 2001

The shared disk file systems use a technique known as file system journaling to support recovery of metadata on the SAN(Storage Area Network). In the existing journaling technique, the metadata that is dirtied by one host must be updated to disk space before some hosts access it. The system performance is decreased because the disk access number is increased. In this paper, we describe a new recovery technique using a global buffer to decrease disk I/O. It transmits the dirtied metadata into the other hosts through Fibre Channel network on the SAN instead of disk I/O and supports recovery of a critical data by journaling a data as well as metadata.

• The Journal of Korean Institute of Next Generation Computing
• /
• v.13 no.3
• /
• pp.26-33
• /
• 2017

Recently container technologies have been receiving attention for efficient use of the cloud platform. Container virtualization technology has the advantage of a highly portable, high density when compared with the existing hypervisor. Container virtualization technology, however, uses a virtualization technology at the operating system level, which is shared by a single kernel to run multiple instances. For this reason, the feature of container is that the attacker can obtain the root privilege of the host operating system internal the container. Due to the characteristics of the container, the attacker can attack the root privilege of the host operating system in the container utilizing the vulnerability of the kernel. In this paper, we propose a framework for efficiently detecting and responding to root privilege attacks of a host operating system in a container. This framework uses a memory trap technique to detect changes in a specific memory area of a container and to suspend the operation of the container when it is detected.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.10 no.4
• /
• pp.145-150
• /
• 2010

In this paper, we propose additional data transmission system for spectrum efficiency improvement and derive channel capacity formula as a approximated closed-form. Spread spectrum watermarking scheme is selected for the watermarking embedder. Nakagami-q (Hoyt) model is considered as a multipath fading channel. Numerical results show the channel capacity variation of the proposed system in wireless fading channel. From the results, we confirm that the channel capacity of the watermarking system is affected by the fading coefficient and system parameters such that host sampling frequency, host-to-watermark ratio, watermark-to-noise ratio, and PN sequence length.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2016.04a
• /
• pp.51-54
• /
• 2016

NTB는 transparent bridge와 공통적으로 독립적인 PCI bus(PCI 또는 PCI Express bus)에 대해서 데이터 전송 경로(path)를 제공한다는 점에서 기능적으로 유사하다. 그러나, NTB와 transparent bridge 간의 가장 큰 차이점은 NTB가 사용될 경우에 bridge의 하향부분(downstream side)에 위치한 장치들은 상향부분(upstream side)에서는 보이지 않는다는 점이다. 이는 bridge의 하향부분(downstream side)에 위치한 인텔리전트(intelligent)한 제어기(예를들면 CPU를 포함하는 컴퓨터)가 자신의 downstream side에 위치하는 서브시스템 내 각종 장치들을 독립적으로 관리할 수 있다는 점이다. NTB는 또한 첫 번째 호스트(primary host)의 PCI bus로 구성된 서브시스템(subsystem) 계층구조(hierarchy)에 두 번째 호스트(secondary host)를 연결하는 데 사용될 수 있다. 이는 두 시스템간 통신을 가능하도록 하는 반면, 두 시스템을 서로 격리시키는 효과도 발생한다. 즉, NTB는 일반적으로 도어벨(doorbell)을 통해서 bridge의 다른 편에 위치한 장치에 대해서 인터럽트를 보낼 수 있으며, 또한, scratchpad 레지스터를 보유하고 있어 bridge의 양측에서 데이터를 상호 공유함으로써 interprocessor communication 할 수 있다.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.16 no.4
• /
• pp.69-81
• /
• 2006

The Computer Forensics is a research area that finds the malicious users by collecting and analyzing the intrusion or infringement evidence of computer crimes such as hacking. Many researches about Computer Forensics have been done so far. But those researches have focussed on how to collect the forensic evidence for both analysis and poofs after receiving the intrusion or infringement reports of hosts from computer users or network administrators. In this paper, we describe how to collect the forensic evidence of good quality from observable and protective hosts at the time of infringement occurrence by malicious users. By correlating the event logs of Intrusion Detection Systems(IDSes) and hosts with the configuration information of hosts periodically, we calculate the value of infringement severity that implies the real infringement possibility of the hosts. Based on this severity value, we selectively collect the evidence for proofs at the time of infringement occurrence. As a result, we show that we can minimize the information damage of the evidence for both analysis and proofs, and reduce the amount of data which are used to analyze the degree of infringement severity.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.16 no.6
• /
• pp.177-181
• /
• 2016

This paper analyzes the host cache effectiveness in full virtualization, particularly associated with journaling of guests. We observe that the journal access of guests degrades cache performance significantly due to the write-once access pattern and the frequent sync operations. To remedy this problem, we design and implement a novel caching policy, called PDC (Pollution Defensive Caching), that detects the journal accesses and prevents them from entering the host cache. The proposed PDC is implemented in QEMU-KVM 2.1 on Linux 4.14 and provides 3-32% performance improvement for various file and I/O benchmarks.

• Proceedings of the Korean Information Science Society Conference
• /
• 2001.10c
• /
• pp.568-570
• /
• 2001

최근에 들어와 그 응용분야가 확대되어 가고 있는 에이전트 소프트웨어는 점점 그 크기와 복잡성이 커져 감에 따라 소프트웨어 개발치 효율성을 필요로 하는 추세이다. 이에 따라 네트워크에 분산되고 이질적인 시스템에 존재하는 에이전트들은 자신의 정보를 효율적으로 교환할 수 있도록 하기 위해 통신 프레임웍을 필요로 하게 되었다. 본 논문에서는 네트워크에 존재하고 동일한 환경 또는 서로 다른 환경에 존재하는 에이전트들 간의 의사 소통을 위한 통신 프레임웍의 설계 및 구현을 제시한다. 기본적으로 에이전트 소프트웨어 아키텍처는 KRIL(KQML- Router Interface Labrary), Router, Facilitator로 구성되어 진다. 같은 호스트에 존재하는 에이전트들은 같은 주소를 가지기 때문에 각기 다른 Router를 가질 필요 없이 하나의 Router를 공유한다. Router는 로컬 호스트에 존재하는 에이전트들의 리스트를 유지 관리하며, 로컬 에이전트가 보낸 메시지의 수신자가 자신의 리스트에 없을 경우 Facilitator를 통해 다른 호스트에 존재하는 에이전트에 메시지를 전달한다. 서로 다른 환경에 존재하는 에이전트들 간의 통신과 스레드 관리, 병행처리와 동기화 등을 위해 KRIL은 ACE(The Adaptive Communication Environment) 라이브러리를 사용하였으며, Router와 Facilitator는 Java로 구현하였다.

• Journal of KIISE:Computing Practices and Letters
• /
• v.9 no.4
• /
• pp.393-409
• /
• 2003

In this paper, we present a multi-task debugging environment for Qplus-T embedded-system such as internet information appliances. We will propose the structure and functions of a remote multi-task debugging environment supporting environment effective ross-development. And, we are going enhance the communication architecture between the host and target system to provide more efficient cross-development environment. The remote development toolset called Q+Esto consists to several independent support tools: an interactive shell, a remote debugger, a resource monitor, a target manager and a debug agent. Excepting a debug agent, all these support tools reside on the host systems. Using the remote multi-task debugger on the host, the developer can spawn and debug tasks on the target run-time system. It can also be attached to already-running tasks spawned from the application or from interactive shell. Application code can be viewed as C/C++ source, or as assembly-level code. It incorporates a variety of display windows for source, registers, local/global variables, stack frame, memory, event traces and so on. The target manager implements common functions that are shared by Q+Esto tools, e.g., the host-target communication, object file loading, and management of target-resident host tool´s memory pool and target system´s symbol-table, and so on. These functions are called OPEn C APIs and they greatly improve the extensibility of the Q+Esto Toolset. The Q+Esto target manager is responsible for communicating between host and target system. Also, there exist a counterpart on the target system communicating with the host target manager, which is called debug agent. Debug agent is a daemon task on real-time operating systems in the target system. It gets debugging requests from the host tools including debugger via target manager, interprets the requests, executes them and sends the results to the host.

• Journal of the Institute of Electronics Engineers of Korea TE
• /
• v.39 no.1
• /
• pp.77-82
• /
• 2002

IDS has been studied mainly in the field of the detection decision and collecting of audit data. The detection decision should decide whether successive behaviors are intrusions or not , the collecting of audit data needs ability that collects precisely data for intrusion decision. Artificial methods such as rule based system and neural network are recently introduced in order to solve this problem. However, these methods have simple host structures and defects that can't detect changed new intrusion patterns. So, we propose the method using data mining that can retrieve and estimate the patterns and retrieval of user's behavior in the distributed different hosts.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2001.05a
• /
• pp.676-679
• /
• 2001

As network security is coning up with significant problem after the major Internet sites were hacked nowadays, IDS(Intrusion Detection System) is considered as a next generation security solution for more reliable network and system security rather than firewall. In this paper, we propose the new IDS model which tan detect intrusion in different systems as well as which ran make real-time detection of intrusion in the expanded distributed environment in host level of drawback of existing IDS. We implement its prototype and verify its validity. We use pattern extraction agent so that we can extract automatically audit file needed in distributed intrusion detection even in other platforms.