• Journal of Internet Computing and Services
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• v.10 no.2
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• pp.1-13
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• 2009

Intrusion detection is a process that identifies the attacks and responds to the malicious intrusion actions for the protection of the computer and the network resources. Due to the fast development of the Internet, the types of intrusions become more complex recently and need immediate and correct responses because the frequent occurrences of a new intrusion type rise rapidly. Therefore, to solve these problems of the intrusion detection systems, we propose a sequential pattern miner for analysis of the alert data in order to support intelligent and automatic detection of the intrusion. Sequential pattern mining is one of the methods to find the patterns among the extracted items that are frequent in the fixed sequences. We apply the prefixSpan algorithm to find out the alert sequences. This method can be used to predict the actions of the sequential patterns and to create the rules of the intrusions. In this paper, we propose an extended prefixSpan algorithm which is designed to consider the specific characteristics of the alert data. The extended sequential pattern miner will be used as a part of alert data analyzer of intrusion detection systems. By using the created rules from the sequential pattern miner, the HA(high-level alert analyzer) of PEP(policy enforcement point), usually called IDS, performs the prediction of the sequence behaviors and changing patterns that were not visibly checked.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.59.1-59
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• 2001

The attackers on Internet-connected systems we are seeing today are more serious and more technically complex than those in the past. Computer security incidents are different from many other types of crimes because detection is unusually difficult. So, network security managers need a IDS and Firewall. IDS (Intrusion Detection System) monitors system activities to identify unauthorized use, misuse or abuse of computer and network system. It accomplishes these by collecting information from a variety of systems and network resources and then analyzing the information for symptoms of security problems. A Firewall is a way to restrict access between the Internet and internal network. Usually, the input ...

• Economic and Environmental Geology
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• v.7 no.3
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• pp.123-152
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• 1974

The study focused to the so called "Yangpyeong Igneous Complex" which intruded into the Gyeong Gi gneiss complex of Pre-cambrian basement of Yangpyeong area. The geologic sequence of the mapped area was shown in table 1. In laboratory work, 31 modal analyses and 7 chemical analyses on the rock samples taken from the igneous complex have been made to discuss the nomenclature of the rocks and the petrological relationship between rock types. The petrographical and petrochemical features based on the analyses are as follow; 1) The classification of this rocks based on the systematics of igneous rocks of IUGS showed that Yangpyeong Igneous complex consist of hornblende gabbro, diorite and porphyritic monzonite. The major rock forming minerals in hornblende gabbro are hornblende and plagiodase ($An_{46{\sim}55}$), in diorite, hornblende, biotite and plagioclase ($An_{23{\sim}33}$) and in porphyritic monzonite, K-feldspar, plagioclase ($An_{21{\sim}35}$), hornblende and biotite. Hornblende gabbro and diorite show coarse to medium grained hypidiomorphic granular texture and porphyritic monzonite was named by the characteristically porphyritic texture of K-feldspar phenocrysts. 2) Silica-oxides variation diagram (Fig.4) illustrate that the igneous complex is similar ttl that of Daly's average basalt-andesite-dacite-rhyolite and equivalent to the calc-alkalic rock series of Peacock's rock series. In AMF diagram (Fig. 5), the trend of the igneous complex is nearly pararell to that of the Skaergaard intrusion which shows the trend of the fractional crystalization of magma. 3) In normative Or-Ab-An diagram (Fig. 6) the general trend of the data points from gabbro to porphyritic monzonite of the igneous complex directs to a point of Or/Ab=1:1 on the side of Or-Ab. The field and laboratory evidences suggested that the Yangpyeong igneous complex was thought to be a series of comagmatic differential products.

• Journal of Communications and Networks
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• v.11 no.6
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• pp.544-555
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• 2009

This work continues a trend of developments aimed at exploiting the physical layer of the open systems interconnection (OSI) model to enhance wireless network security. The goal is to augment activity occurring across other OSI layers and provide improved safeguards against unauthorized access. Relative to intrusion detection and anti-spoofing, this paper provides details for a proof-of-concept investigation involving "air monitor" applications where physical equipment constraints are not overly restrictive. In this case, RF fingerprinting is emerging as a viable security measure for providing device-specific identification (manufacturer, model, and/or serial number). RF fingerprint features can be extracted from various regions of collected bursts, the detection of which has been extensively researched. Given reliable burst detection, the near-term challenge is to find robust fingerprint features to improve device distinguishability. This is addressed here using wavelet domain (WD) RF fingerprinting based on dual-tree complex wavelet transform (DT-$\mathbb{C}WT$) features extracted from the non-transient preamble response of OFDM-based 802.11a signals. Intra-manufacturer classification performance is evaluated using four like-model Cisco devices with dissimilar serial numbers. WD fingerprinting effectiveness is demonstrated using Fisher-based multiple discriminant analysis (MDA) with maximum likelihood (ML) classification. The effects of varying channel SNR, burst detection error and dissimilar SNRs for MDA/ML training and classification are considered. Relative to time domain (TD) RF fingerprinting, WD fingerprinting with DT-$\mathbb{C}WT$ features emerged as the superior alternative for all scenarios at SNRs below 20 dB while achieving performance gains of up to 8 dB at 80% classification accuracy.

• Wind and Structures
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• v.23 no.5
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• pp.449-464
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• 2016

Catastrophe models appraise the natural risk of the built-infrastructure simulating the interaction of its exposure and vulnerability with a hazard. Because of unique configurations and reduced number, mid/high-rise buildings present singular challenges to the assessment of their damage vulnerability. This paper presents a novel approach to estimate the vulnerability of mid/high-rise buildings (MHB) which is used in the Florida Public Hurricane Loss Model, a catastrophe model developed for the state of Florida. The MHB vulnerability approach considers the wind pressure hazard exerted over the building's height as well as accompanying rain. The approach assesses separately the damages caused by wind, debris impact, and water intrusion on building models discretized into typical apartment units. Hurricane-induced water intrusion is predicted combining the estimates of impinging rain with breach and pre-existing building defect size estimates. Damage is aggregated apartment-by-apartment and story-by-story, and accounts for vertical water propagation. The approach enables the vulnerability modeling of regular and complex building geometries in the Florida exposure and elsewhere.

• Economic and Environmental Geology
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• v.14 no.3
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• pp.123-142
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• 1981

Granitic complex in the Woosanbong area is composed of schistose granite, two-mica granite, biotite granite, porphyritic granite and pink feldspar granite in order of intrusion. In their boundary aspects, the gradational change between porphyritic granite and pink feldspar granite is observed in field relations. All the granites of the complex are classified to quartz monzonite by the modal compositions following Bateman's classification (1961) with the exception of pink feldspar granite which belongs to granite according to the petrographical classification. The first three granites are characterized by highly development of vein and/or lens-like pegmatites in their bodies, and two others contain green hornblende uniquely. These leucocratic two-mica granite shows an unusual character in ratio of muscovite to biotite 1: 0.7 to 1:13, and contains dominantly microcline. The content of muscovite varies in places in the field. Under the polarizing microscope it is revealed that the muscovite flakes occur as the products altered from biotite partly or completely, and it usually associates with chlorite flakes nearby. These features, therefore, suggests that biotite probably has been altered to muscovite and chlorite by hydration during deuteric processes. At the same stage, sericitization of plagioclase by the hydrolytic decomposition, and transformation of orthoclase to microcline may be taken place. Accordingly, it is obviously permissible to consider the two-mica granite as a kind of 'apo-granite' by deuteric alterations during the consolidation of magma.

• The Journal of the Petrological Society of Korea
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• v.5 no.2
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• pp.168-187
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• 1996

In the study area Uanggunbong-Samgunri area), Precambrian metamorphic complex, (Taebacksan gneiss complex, Hyundong gneiss complex, and Taebacksan schist complex) had undergone three different regional metamorphisms at least before Paleozoic. The Paleozoic sediments in the study area also had undergone three different metamorphisms at least. The first is low pressure type regional metamorphism, the second is low pressure type contact metamorphism due to the intrusion of Chunyang granite, and the last is medium pressure type metamorphism caused by thrust in south of Janggunbong area. The first metamorphism formed the prevailing metamorphic zones in the Paleozoic metasediments and the metamorphic grade of the first regional metamorphism increases from the chloritoid zone, through the staurolite zone, garnet zone, staurolite+biotite zone, and to the andalusite+biotite zone. The second metamorphism affected both Pre-Cambrian and Paleozoic metasediments located close to the Chunyang granite. The effect of the contact metamorphism is restricted to the very narrow zone around the granite. The third metamorphism that produced kyanite, is restricted to the very narrow region near the thrust fault in the south of Janggunbong with an E-W trend.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2010.05a
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• pp.271-272
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• 2010

Sensitivity analysis by TSUNAMI clarifies the complex effects of key nuclides on the criticality probability quantitatively. As discussed above, the $K_{eff}$ of $UO_2$ fuel reaches the maximum value with 42w% concentration of intrusion water. The concentration of hydrogen affects the complexity of reaching criticality by its competition between the concentrations of $^{235}U$. Approximately if the weight percent of $H_2O$ in the mixture is less than 42%, the moderation effect of hydrogen surpasses its dilution effect on $^{235}U$. However, the importance of $^{235}U$ increases dramatically when the weight percent of water is bigger than 42%. In the sensitivity evaluation of $UO_2$ fuel employing TSUMAMI, there is a similar crosspoint of the sensitivity of $^{235}U$ and the sensitivity of $^1H$ where the criticality reaches summit. And the optimal water weight percent is determined to be 50%.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.198-204
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• 2001

Train crashes involve complex interaction between deformable bodies in multiple collisions. The purpose of this study is to suggest the effective analytical procedure using hybrid model for the crashworthiness of motorized trailer of high speed train. The hybrid approach, with very short modeling times and reduced computation times to extract the global behaviour and to perform a pre-optimization of the considered structure. Firstly, various types of crash events are investigated and the conditions for numerical simulation are defined. In this paper, the structural crashwonhiness of Korean High Speed Train trailer was examined through FE analysis. Crash analyses on energy absorbing part and safety zone were carried out to determine each section force. Rollover analysis was performed to observe the amount of intrusion in the passenger's area in case of rollover accident.

• Journal of Communications and Networks
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• v.16 no.4
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• pp.407-414
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• 2014

The Internet is a highly distributed and complex system consisting of billion devices and has become the field of various kinds of conflicts during the last two decades. As a matter of fact, various actors utilise the Internet for illicit purposes, such as for performing distributed denial of service attacks (DDoS) and for spreading various types of aggressive malware. Despite the fact that numerous services provide information regarding the threat level of the Internet, they are mostly based on information acquired by their sensors or on offline statistical sampling of various security applications (antivirus software, intrusion detection systems, etc.). This paper introduces proactive threat observatory system (PROTOS), an open-source early warning system that does not require a commercial license and is capable of estimating the threat level across the Internet. The proposed system utilises both a global and a local approach, and is thus able to determine whether a specific host is under an imminent threat, as well as to provide an estimation of the malicious activity across the Internet. Apart from these obvious advantages, PROTOS supports a large-scale installation and can be extended even further to improve the effectiveness by incorporating prediction and forecasting techniques.