• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.1
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• pp.39-52
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• 2011

An application-layer attack can effectively achieve its objective with a small amount of traffic, and detection is difficult because the traffic type is very similar to that of legitimate users. We have discovered a unique characteristic that is produced by a difference in client intention: Both a legitimate user and DDoS attacker establish a session through a 3-way handshake over the TCP/IP layer. After a connection is established, they request at least one HTTP service by a Get request packet. The legitimate HTTP user waits for the server's response. However, an attacker tries to terminate the existing session right after the Get request. These different actions can be interpreted as a difference in client intention. In this paper, we propose a detection algorithm for application layer DDoS attacks based on this difference. The proposed algorithm was simulated using traffic dump files that were taken from normal user networks and Botnet-based attack tools. The test results showed that the algorithm can detect an HTTP-Get flooding attack with almost zero false alarms.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.108-110
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• 2021

Since 2015, attacks using the IoT protocol have been continuously reported. Among various IoT protocols, attackers attempt DDoS attacks using SSDP(Simple Service Discovery Protocol), and as statistics of cyber shelters, Korea has about 1 million open SSDP servers. Vulnerable SSDP servers connected to the Internet can generate more than 50Gb of traffic and the risk of attack increases gradually. Until recently, distributed denial of service attacks and distributed reflective denial of service attacks have been a security issue. Accordingly, the purpose of this study is to analyze the request packet of the existing SSDP protocol to identify an amplification attack and to avoid a response when an amplification attack is suspected, thereby preventing network load due to the occurrence of a large number of response packets due to the role of traffic reflection amplification.

• Journal of The Korean Association For Science Education
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• v.24 no.5
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• pp.959-976
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• 2004

The purpose of this study was to investigate high school students' ideas related with dinosaur extinction, to classify students' responses types with alternative hypotheses of inconsistent with their ideas, and then to examine their cognitive conflict levels and the degree of ideas change. To investigate students' ideas, we analyzed responses 98 eleventh graders of a high school in Anyang area. The results of this study were as follows: First, most of the students responded a large scale asteroid impact with the cause of dinosaur extinction, and rest of them responded changed Earth's climate accompanying tectonic activity, extreme volcanic activity, shortage of food, disease(virus) and decrease of their habitat. Also, they thought that dinosaur was exterminated not by just one reason but by several complex reasons. Second, the students' responses of alternative hypotheses were classified into six types: rejection, reinterpretation, uncertainty, belief decrease, partial theory change, and theory change. Third, except rejection and reinterpretation types, other four types were arousing of cognitive conflict and the percentage of the students who felt cognitive conflict was 62.3% and that of the students who took the theory change was just 6.1 %.

• The Journal of the Korea Contents Association
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• v.20 no.12
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• pp.406-416
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• 2020

The purpose of this study is to confirm the effect of parents' positive and negative parenting attitudes perceived by children on smartphone dependence. In addition, it is to verify whether aggression and social withdrawal play a mediating role in the relationship between parental attitude and dependence on smartphones. In order to achieve this goal, the data of the "Korean Children and Youth Panel Survey 2018(KCYPS 2018)" were used for analysis. The sample group is 2,399 "elementary school students 4 cohort". The research results of this study are as follows. First, it was found that autonomy support and coercion had a negative effect on aggression of children, but rejection and inconsistency had a positive effect on aggression. Second, it was found that inconsistency and rejection had a positive effect on children's social atrophy, but coercion had a negative effect. Third, it was found that aggression had a positive effect on children's dependence on smartphones, but social withdrawal had no significant effect. Fourth, it was found that autonomy support, rejection, coercion, and inconsistency indirectly affect children's dependence on smartphones through aggression. In this study's conclusion, practical implications for lowering children's dependence on smartphones were suggested.

• The Journal of the Korea Contents Association
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• v.20 no.10
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• pp.436-448
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• 2020

This study aims to determine the effect of e-cigarettes on oral health by investigating the association between the use of different tobacco products and oral health among Korean adults aged 19 years and older. Data from the 2017 Community Health Survey were used for the study. Respondents were divided into four groups: non-smokers, cigarette smokers, e-cigarette smokers, and users of both products. A sample of 228,357 respondents was selected for analysis. Twenty-four questionnaires with missing values (non-response or refusal) were excluded from the sample. A regression analysis was performed with oral as the dependent variable. A multivariate regression analysis showed a significant difference between cigarette smokers and users of both products when compared to the non-smokers. However, e-cigarette users showed a significant when the variables were correlated with age and gender. There was no significant difference in other dependent variables in a multivariate regression analysis. The results of the study indicated no association between e-cigarette use and oral health. More research is needed on factors such as amount and intensity of e-cigarette use.

• Journal of the Korean Society of Food Culture
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• v.16 no.1
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• pp.65-72
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• 2001

본 연구는 상품화된 육수 재료의 이용 현황 및 소비자 의견을 조사하기 위하여 수행되었고 이를 위해 서울에 거주하는 500명의 주부를 대상으로 설문조사를 실시하였다. 그 결과, 사용하는 제품의 종류는 분말형이 가장 많았고 시간 절약과 편리함이 상품화된 육수재료를 사용하는 가장 주된 이유였다. 또한 육수 재료를 사용하는 방법으로는 육류로 만든 육수에 섞어서 사용하는 방법이 가장 많이 쓰이고 있었다. 상품화된 육수 재료의 기호도에 대해서는 응답자의 81%가 상품화된 육수에 대해 '좋아하지 않는다'라고 하였다. 좋아하지 않는 가장 큰 이유는 '첨가제에 대한 염려와 인공조미료 때문'이었다. 연령이 높고 결혼지속년수가 길수록 상품화된 육수 재료를 좋아하지 않는 비율은 높아졌다. 상품화된 육수가 품질만 보장된다면 응답자의 75%는 사용할 의사가 있는 것으로 나타났으나 나머지는 아무리 좋은 품질이라 해도 육수는 직접 제조하겠다고 응답하였다. 60대 이상의 응답자들만은 상품화된 육수를 사용하지 않겠다는 비율이 더 높아 60대 이상의 고령층은 상품화된 육수 제품에 대해 가장 거부감이 큰 연령대인 것으로 판단된다. 본 연구 결과, 상품화된 육수의 수요는 크나 시판되는 제품들에 대한 만족도는 낮은 것으로 나타났으므로 소비자 요구를 반영한 육수 제품에 대한 연구가 시급한 것으로 생각된다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1428-1431
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• 2009

현재 사이버 공간에서 일어나고 있는 정보보호 위반사건들은 이미 실생활에 구체적인 악영향을 미치고 있고 이런 정보보호 관련 이슈사항에 대한 여러 보완 및 개선 방안이 제시되고 있다. 그런데 분산 서비스거부공격(DDoS)에 의한 피해규모는 나날이 커지는 반면에 인터넷의 구조적 특성으로 명확한 대응책보다는 조기탐지를 통해 사전에 대응함으로써 피해규모를 줄이거나 공격을 완화시켜 가용성을 확보하는 방법만 고안되고 있다. 그러나 우리는 공격을 완화시켜 주는 추가적인 고가의 네트워크 장비 구축 없이 기존 시스템을 활용한 분산 방화벽 모델을 제안한다. DDoS 공격이 이루어질 때 방화벽의 세션테이블과 간단한 관리기능을 그리드 컴퓨팅 기법 중 하나인 워크릿(worklet)으로 구성하여 방화벽 하위 웹 서버 군(group)에 배포시켜 각각의 웹 서버가 방화벽의 세션테이블 기능을 부분적으로 수행하는 것이다. 이렇게 함으로써 공격이 진행되는 중이라도 기존 구조에서는 할 수 없었던 정당한 인터넷 서비스 요청에 응답할 수 있어 가용성이 증대되는 효과를 얻을 수 있다.

• Korean Journal of Culture and Social Issue
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• v.13 no.1
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• pp.1-41
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• 2007

This study examines factors that influence delinquent behavior among Korean adolescents using longitudinal analysis. A total of 1,012 students completed a questionnaire when they were Grade 6 and 739 students completed a follow-up questionnaire when they became Grade 9. Results of multiple regression analysis indicate that the following variables predicted delinquent behavior of Grade 9 students: Bullying, previous delinquency, experience of punishment, victimization, social efficacy, and moral disengagement. The above six variables have direct and mediating influence of delinquent behavior. Relational factors also influenced delinquent behavior. Social exclusion from friends reduce social efficacy, which increases victimization and which in turn increases bullying, leading to greater delinquency. Parental rejection, social exclusion from friends and hostility from teachers increase moral disengagement, which increases bullying, leading to delinquency. Low academic achievement increases the likelihood of being punished, which increases bullying, leading to delinquency. The results indicate that moral disengagement and social efficacy are mediating factors of delinquency and negative life-events (i.e., social exclusion from friends, rejection from teachers, hostility from parents and low academic achievement) increase the likelihood that Korean adolescents will engage in delinquent behavior. Implications of the results for future research are discussed.

• Korean Journal of Culture and Social Issue
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• v.13 no.1
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• pp.43-61
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• 2007

Most previous research on safer sex and condom use has been mainly focused on individual's dispositional factors such as attitudes, perceived control, intention, and etc. However, a few researchers recently started to propose that condom use is not a matter of individual behavioral decision but a product of serious interactive negotiation processes and condom negotiation would be the proximal key-determinant of condom use behaviors. The present research categorized condom-negotiation strategies and preferences of Korean college students and examined relationship between the strategies and other sex-related concepts. 186 participants' strategies on a free-response questions of condom negotiation revealed 7 types of persuasion strategies for condom use; Pregnancy risk, responsibility, care for partner, withholding sex, sexual disease, direct request, and sexual satisfaction (in order of preference). 6 types of persuasion strategies for condom avoid were abstracted: Pregnancy free, Sexual satisfaction, responsibility, direct request, unfaith toward condom, and withholding sex (in order of preference). The effects of gender, sexual experience, and culture were found and discussed in their implications for sexual education,

• Journal of Hospice and Palliative Care
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• v.15 no.1
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• pp.10-17
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• 2012

Purpose: This study was conducted to identify the perception regarding palliative care among Korean doctors and referral barriers toward palliative care for terminal cancer patients. Methods: Between May and June 2010, 477 specialists mainly caring cancer patients using a web-based, self-administered questionnaire. Results: A total of 128 doctors (26.8%) responded. All respondents (100%) deemed palliative care a necessary service for terminal cancer patients. More than 80% of the respondents agreed to each of the following statements: all cancer centers should provide palliative care service (80.5%); all terminal cancer patients should receive concurrent palliative care along with anti-cancer therapies (89.1%) and caring for terminal cancer patients requires interdisciplinary approach (96.9). While more than 58% of the respondents were satisfied with their performance of physical and psychological symptoms management and emotional support provided by patient's family members, 64% of the responded answered that their general management of the end-of-life care was less than satisfactory. Doctors without prior experience in referring their patients to palliative care specialists accounted for 26.6% of the respondents. The most common barrier to hospice referral, cited by 47.7% of the respondents, was "refusal of patient or family member", followed by "lack of available palliative care resources" (46.1%). Conclusion: Although most doctors do recognize the importance of palliative care for advanced cancer patients, comprehensive and sufficient palliative medicine, including interdisciplinary cooperation and end-of-life care, has not been put into practice. Thus, more active palliative consultation or referral is needed for effective care of terminal cancer patients.