• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2101-2105
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• 2003

Recently the number of Internet users has very sharply increased, and the number of intrusions has also increased very much. Consequently, security products are being developed and adapted to prevent systems and networks from being hacked and intruded. Even if security products are adapted, however, hackers can still attack a system and get a special authorization because the security products cannot prevent a system and network from every instance of hacking and intrusion. Therefore, the researchers have focused on an active hacking prevention method, and they have tried to develop a traceback system that can find the real location of an attacker. At present, however, because of the characteristics of Internet - diversity, anonymity - the real-time traceback is very difficult. To over-come this problem the Network-based Real-Time Connection Traceback System (NRCTS) was proposed. But there is a security problem that the victim system can be hacked during the traceback. So, in this paper, we propose modified NRCTS with connection redirection technique. We call this traceback system as Connection Redirected Network-based Real-Time Connection Traceback System (CR-NRCTS).

• Journal of Information Processing Systems
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• v.7 no.1
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• pp.137-150
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• 2011

Mobile ad hoc networks are expected to be widely used in the near future. However, they are susceptible to various security threats because of their inherent characteristics. Malicious flooding attacks are one of the fatal attacks on mobile ad hoc networks. These attacks can severely clog an entire network, as a result of clogging the victim node. If collaborative multiple attacks are conducted, it becomes more difficult to prevent. To defend against these attacks, we propose a novel defense mechanism in mobile ad hoc networks. The proposed scheme enhances the amount of legitimate packet processing at each node. The simulation results show that the proposed scheme also improves the end-to-end packet delivery ratio.

• ETRI Journal
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• v.38 no.5
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• pp.903-910
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• 2016

We propose a novel multi-stack (MS) technique for a compact and wideband electromagnetic bandgap (EBG) structure in high-speed multilayer printed circuit boards. The proposed MS technique efficiently converts planar EBG arrays into a vertical structure, thus substantially miniaturizing the EBG area and reducing the distance between the noise source and the victim. A dispersion method is presented to examine the effects of the MS technique on the stopband characteristics. Enhanced features of the proposed MS-EBG structure were experimentally verified using test vehicles. It was experimentally demonstrated that the proposed MS-EBG structure efficiently suppresses the power/ground noise over a wideband frequency range with a shorter port-to-port spacing than the unit-cell length, thus overcoming a limitation of previous EBG structures.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.4
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• pp.89-96
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• 2014

MANET has been applied to a wide variety of areas because it has advantages which can build a network quickly in a difficult situation to build a network. However, it is become a victim of malicious nodes because of characteristics such as mobility of nodes consisting MANET, limited resources, and the wireless network. Therefore, it is required to lightweight attack detection technique which can accurately detect attack without causing a large burden to the mobile node. In this paper, we propose a multistage attack detection techniques that attack detection takes place in routing phase and data transfer phase in order to increase the accuracy of attack detection. The proposed attack detection technique is composed of four modules at each stage in order to perform accurate attack detection. Flooding attack and packet discard or modify attacks is detected in the routing phase, and whether the attack by modification of data is detected in the data transfer phase. We assume that nodes have a public key and a private key in pairs in this paper.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.2
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• pp.296-303
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• 2010

The term "spoofing" refers to the transmission of counterfeit signals to provide undetectable falsification of GPS service. A spoofing can be accomplished using information from open literature which defines the signal format and the data structure. Spoofing is intended either to produce erroneous navigation solutions or saturate the processor of the victim receiver. The GPS receiver has no way to get rid of the effect of a spoofing because GPS receivers for civil service do not have an anti-spoofing scheme. This paper analyzes the spoofing characteristics, spoofing methods and environment conditions. And the spoofing effects on GPS receiver are analyzed in detail using the designed software-based spoofer and the Nordnav receiver.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.19 no.3
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• pp.162-167
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• 2008

Objectives: The aim of this study was to identify characteristics of children and adolescents who were victims of sexual assault in Korea. Methods: The subjects were 60 children and adolescents who visited the one-stop center as victims of sexual assault. The medical records of victims of sexual trauma were retrospectively reviewed. We studied the demographic data of the victims, their relationship to their perpetrator, the characteristics of the assault (frequency, duration, place, type), and the process from sexual assault to treatment. We also paid special attention to how the characteristics of the victims or perpetrators affected the characteristics of the assault or follow-up treatment. Results: There were several differences between sexual assaults committed by strangers and those committed by acquaintances. Sexual assaults committed by acquaintances lasted for a longer period of time than those committed by strangers. In addition, it took more time for victims of sexual assaults committed by acquaintances to seek treatment than those who were victims of sexual assaults committed by strangers. The majority (55.0%) of victims were between 10 and 15 years of age. Forty percent of the perpetrators were teenagers, and two of them were under the age of 10. Voluntary discontinuation of treatment was more frequent in adolescents than in children. Conclusion: All teenage victims of sexual assault need some sort of urgent intervention. In addition, approachable methods are needed in order to prevent sexual abuse by strangers or acquaintances.

• Architectural research
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• v.14 no.2
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• pp.45-56
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• 2012

The high rate of urban crime is a main issue that needs to be dealt with in this high-tech society. With the rapid increase of urban crime, research has mainly focused on topics either on a global or a local scale, such as cities or communities and houses or buildings, without reliable observational data. This study makes the best use of the nationwide surveys carried out by Korean government agencies for the analysis of urban crime patterns and factors in major Korean cities. The aims of this research are threefold: understanding the relationship between urban crime patterns and socio-economic differences in cities, determining the effect of residence types on the urban crime patterns; and uncovering potential influential factors of a crime victim's individual characteristics. The statistical methods used for the analysis of social statistical data are as follows: simple regression, logistic regression, one-way ANOVA and post-hoc test. This research found that the patterns of urban crime rate in cities have a certain tendency toward the cities' socio-economic and geographical differences. The residence type is an influential factor showing a close relation to the crime rate. Personal issues, such as the types of occupation, education, marriage, etc., are directly relevant to victims of crime.

• The Journal of Korean Academic Society of Nursing Education
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• v.21 no.2
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• pp.246-255
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• 2015

Purpose: The purpose of this study was to investigate differences in the states of anger, depression, resilience and self-esteem according to type of school violence involving elementary school students. Methods: The participants were 257 elementary school students in the 4th, 5th and 6th grades. Data was collected by structured questionnaires, and analyzed using descriptive statistics, ${\chi}^2$-test, t-test, ANOVA, and Pearson correlation coefficients with the SPSS/WIN 20.0 program. Results: There were significant differences among the states of anger (Fs=16.66, p<.001), depression (Fs=18.04, p<.001), resilience (F=12.77, p<.001) and self-esteem (F=10.39, p<.001) according to the type of school violence. Of all the groups, bully-victim exhibited the highest score for anger and depression, and the lowest score for resilience and self-esteem. Conclusion: Based on the findings, developing intervention programs that consider the psychological characteristics of elementary school students is necessary. Also, the results of this study suggest that integrative programs for students that can enhance resilience and self-esteem, such as self-discovery programs, and reduce anger, such as anger control programs, need to be developed.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.3
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• pp.235-241
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• 2012

The efficiency tests of automatic positioning transmitter (APT) using satellite on life jacket were carried out to minimize casualties of fishermen and to make system optimization for effective SAR (Search and Rescue) operation. As the result of the tests, average position was equaled on the comparison between SPOT using low earth orbit satellite and DGPS (Differential Global Positining System), but standard deviation of DGPS for latitude and longitude were 66.4% and 46.3% smaller than those of SPOT. The position precision of SPOT was almost two times lower than LGT using geostationary satellite to compare 95% circular error probability. However, the success rate of receiver for SPOT was revealed as 86.5~94.1% on the experiments in the South Sea and the West Sea and it was 4.5 times higher than LGT. Therefore, SPOT is expected to contribute greatly to the rapid rescue of victim.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.4
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• pp.143-148
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• 2017

Flash Memory which is light and strong external shock as storage of small electronics like smartphone, digital camera, car black box has been widely used. Since the operation speed of the read operation and the write operation are different from each other, and the flash memory has the feature that it is not possible to overwrite, the delete operation is added to solve these problems. Wear-leveling must also be considered, since the number of erase times of the flash memory is limited. Many studies have been conducted on the substitutional algorithms of flash memory based on these characteristics of recent flash memories. So, to solve the problem that has existing buffer replacement algorithm this thesis divide page into 6 groups and when proposed algorithm select victim page, it consider reference page frequency and page recency.