• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.1
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• pp.155-163
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• 2014

To enhance network efficiency, content-centric networking (CCN) proposes that intermediated network nodes on a content-delivery path temporally cache transmitted contents. Then if an intermediated node receives a content request message (Interest) for previously cached content, the node directly transmits the cached content as a response message (Data) to requestors and finishes the transmission of the received Interest. Since Interest is performed by intermediated network nodes, it is possible to efficiently transmit contents and to effectively solve a network congestion problem caused around contents sources. For that, CCN utilizes both content store to temporarily cache content and pending Interest table (PIT) to record Interest incoming Face. However, it has mentioned the possibility of denial service attack using both the limitation of PIT resource and fake Interests. In this paper, we briefly describe the presented PIT flooding attack utilizing fake Interest. Then we introduce new attack possibility using fake Data and propose a countermeasure for the proposed attack. Also we evaluate the performance of our proposal.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.9
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• pp.675-684
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• 2009

Internet worm can cause a traffic problem through DDoS(Distributed Denial of Services) or other kind of attacks. In those manners, it can compromise the internet infrastructure. In addition to this, it can intrude to important server and expose personal information to attacker. However, current detection and response mechanisms to worm have many vulnerabilities, because they only use local characteristic of worm or can treat known worms. In this paper, we propose a new framework to detect unknown worms. It uses macroscopic characteristic of worm to detect unknown worm early. In proposed idea, we define the macroscopic behavior of worm, propose a worm detection method to detect worm flow directly in IP packet networks, and show the performance of our system with simulations. In IP based method, we implement the proposed system and measure the time overhead to execute our system. The measurement shows our system is not too heavy to normal host users.

• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.307-315
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• 2020

In this study, we investigate child-care teachers' perceptions of emerging technologies, with a particular focus on fields connected to the Fourth Industrial Revolution. More specifically, we explore how satisfied child-care teachers are with existing educational tools, whether they are interested in or willing to use the latest technology within child care, and their perceived likelihood of adopting these new technologies within child care sites. A total of 181 directors and teachers working at child care institutions in Seoul and Gyeonggi Province participated in the survey. The findings are as follows: firstly, child-care teachers were moderately satisfied with current teaching methods and their effects; secondly, child-care teachers were not especially interested in emerging technologies; thirdly, although interest in applying the latest technology to child care sites was moderately high, refusal to use this technology was also somewhat high; fourthly, many agreed that this technology would eventually become common. This study is expected to provide useful information to those planning to introduce the latest technology to child care sites and basic data to improve teacher training.

• Journal of the Korean Chemical Society
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• v.51 no.1
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• pp.93-100
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• 2007

The purposes of this study were to analyze problems in the experiments for comparing properties of a mixture with a compound of iron and sulfur and then to suggest the improved experiments. For this study, the experimental methods in 9th science textbooks described were analyzed and middle school science teachers were asked to conduct the experiment according to the process of the textbook and to point problems of the experiment. Two alternative experiments, which improves the problems of the toxic and provocative experiment and of distinction between a mixture and a compound by magnetic properties, were proposed. The two experiments were applied to the 10 science teachers and 60 students from a “S” middle school. They responded that the experiments were suitable for comparing properties of a mixture and a compound and helpful to understand the concept.

• 한국지구과학회:학술대회논문집
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• 2006.02a
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• pp.83-88
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• 2006

본 연구에서는 교사 스스로 느끼는 평가에 대한 거부감을 최소화하면서 바람직한 평가 전문성 신장 방향과 방법을 제공할 수 있도록 과학교사를 대상으로 한 학생 평가 전문성 자기 진단 프로그램을 개발하였다. 이 프로그램은 자기반성적 관점에서 과학교사 스스로 자신의 학생 평가 전문성을 진단할 수 있는 도구와 이를 이용하여 얻은 진단 결과를 바탕으로 학생 평가 전문성 수준을 가늠해 볼 수 있는 학생 평가 전문성 등급 평정 척도와 학생 평가 전문성 신장을 위한 안내로 구성되어 있다. 이 프로그램을 개발하기 위해 본 연구에서는 과학교사의 학생 평가 전문성의 개념을 탐색하고, 바람직한 학생 평가 전문성 신장의 방향과 방법을 모색하였다. 또한 과학교사의 학생 평가 전문성 요소를 추출하여 범주별로 정리한 다음 학생 평가 전문성 요소별로 구체적인 수준과 상태를 제시한 과학교사의 학생 평가 전문성 기준을 마련하였다. 마련된 기준을 근거로 과학교사의 학생 평가 전문성 자기 진단 프로그램을 개발하였다. 이를 위해 문헌연구와 더불어 수차례의 과학교육전문가 검토 및 협의, 학교 현장 교사들의 검토 및 협의를 거치면서 수정${\cdot}$보완하는 과정을 거쳤다. 본 연구에서 개발한 과학교사의 학생 평가 전문성 자기 진단 프로그램에는 진단 내용에 과학교사의 평가에 관한 지식과 더불어 실무적인 능력과 실제로 행하고 있는 평가의 실천 내용이 포함될 수 있도록 노력하였다. 또한 교사 스스로 자신의 평가 전문성 수준을 가늠해 볼 수 있도록 전형적인 응답 유형과 채점 기준, 해설 및 평가 전문성 등급 평정 척도를 제시했고 진단 결과를 바탕으로 평가 전문성의 부족한 부분을 보완하고 신장시킬 수 있도록 간략한 전문성 신장을 위한 처방과 평가 지향에 따른 교사의 전형적인 유형을 제시하여 자기 진단 프로그램을 사용하는 교사가 전문성 개선 방향과 방법을 설정하는 데 도움을 주고자 했다. 본 연구는 과학교사 자신의 학생 평가 전문성에 대한 환심을 높이고, 이를 진단하고 신장시키는 데 도움을 줄 수 있을 뿐만 아니라, 과학교사의 학생 평가 전문성 신장을 위한 방안을 마련하려는 데에도 좋은 시사점을 제공할 것으로 판단된다. 이를 위해 과학교사의 학생 평가 전문성 진단 프로그램에 제시된 전문성 평정 기준을 좀 더 객관화하고 보완할 수 있도록 많은 교사들에게 이 프로그램을 사용해 보게 하고 그 결과를 분석하는 후속 연구가 필요하다. 또한, 본 연구에서는 진단 운항을 제작하는 데 있어 지구과학 내용을 소재로 사용하였으나 본 연구에 제시된 진단 문항 제작에 관한 해설을 참고하여 다른 과학교과 내용을 소재로 한 진단 문항 제작도 필요할 것으로 보인다.

• Journal of the Korea Society of Computer and Information
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• v.15 no.9
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• pp.99-107
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• 2010

This paper showed that the integrated system to fortify security was much more efficient than the respective system through the analysis of problems from Firewall and IPS system in the existing security systems. The results of problem analysis revealed that there were the delay of processing time and lack of efficiency in the existing security systems. Accordingly, their performance was evaluated by using the separated Firewall, IPS system, and the integrated system. The result of evaluation shows that the integrated security system this paper suggested is five times faster than the existing one in terms of processing speed of response. This paper demonstrated the excellence of the proposed security system is also more than fivefold in session handling per second and six times process speeding in the CPU processing performance. In addition, several security policies are applied, and it provided a fact that it gave an excellent performance when it comes to protecting from harmful traffic attacks. In conclusion, this paper emphasized that fortifying the integrated security system was more efficient than fortifying the existing one considering in various respects such as cost, management, time, space and so on.

• Journal of Convergence for Information Technology
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• v.10 no.12
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• pp.22-30
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• 2020

With the development of information and communication technology, DDoS and DRDoS continue to become security issues, and gradually develop into advanced techniques. Recently, IT companies have been threatened with DRDoS technology, which uses protocols from normal servers to exploit as reflective servers. Reflective traffic is traffic from normal servers, making it difficult to distinguish from security equipment and amplified to a maximum of Tbps in real-life cases. In this paper, after comparing and analyzing the DNS amplification and Memcached amplification used in DRDoS attacks, a countermeasure that can reduce the effectiveness of the attack is proposed. Protocols used as reflective traffic include TCP and UDP, and NTP, DNS, and Memcached. Comparing and analyzing DNS protocols and Memcached protocols with higher response sizes of reflective traffic among the protocols used as reflective traffic, Memcached protocols amplify ±21% more than DNS protocols. The countermeasure can reduce the effectiveness of an attack by using the Memcached Protocol's memory initialization command. In future studies, various security-prone servers can be shared over security networks to predict the fundamental blocking effect.

• Journal of The Korean Association For Science Education
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• v.28 no.8
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• pp.779-785
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• 2008

In this study, we investigated the role of a discrepant event from both cognitive and motivational perspectives in learning the concept of combustion. A preconception test, a test of response to a discrepant event, and a situational interest questionnaire were administered to 433 eighth graders. After learning the concept of combustion, the tests of attention, effort, and conceptual understanding were administered as post-tests. The reponses of 208 students who had been found to possess the target misconception were analyzed. The percentages of rejection and exclusion responses were relatively high compared to the previous studies about density concept, whereas a proportion of belief change was low. The results of the path analysis indicated that situational interest after presenting an alternative hypothesis had a direct effect and an indirect effect via attention and effort on conceptual understanding. Situational interest induced by a discrepant event directly influenced cognitive conflict after presenting an alternative hypothesis.

• Journal of Nutrition and Health
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• v.53 no.2
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• pp.190-202
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• 2020

Purpose: This study aims to evaluate the recognition, purchase, and intake status of edible insects in adults, who are the main consumers of edible insects, and to provide the information necessary to expand the production and consumption of edible insects and related products in the future. Methods: A total of 453 adults (172 males and 281 females) aged 19 years and older were surveyed regarding their awareness of edible insects, purchase and consumption experience, and intention to purchase and consume, and the differences between them were analyzed according to gender and age groups. Data collection took place from December 2018 to January 2019. Results: Those who had knowledge of edible insects accounted for 87.0%, whereas those who had more than average knowledge were 75.9%, suggesting recognition was relatively high. Men had more experience than women in purchasing or consuming edible insects and related products (45.9% vs. 31.0%, p < 0.01). In terms of age, experience was 22.5% in 20-30s, 44.6% in 40-50s, and 63.1% in 60s and older, showing significant growth as age increased (p < 0.001). The satisfaction level of edible insects was highest in taste (3.4 points), and especially for shape and appearance, it decreased as age reduced (p < 0.001). The most common reason for not being willing to use edible insects was feeling repulsive (4.1 points), which was significantly more common in women than in men (4.3 vs. 3.9, p < 0.001), and lower with age (p < 0.001). The most needed information display for using edible insects was country of origin (63.8%), the main nutrient in edible insects was protein (93.6%), and the most preferred form of products was powder (39.5%). Conclusion: According to the above results, the recognition of edible insects was high, whereas experience of using edible insects and intention to use edible insects were low especially in women and younger groups. The reason for this is that consumers are dissatisfied with edible insects due to their appearance. This study is expected to be used as basic data for expanding the production and consumption of edible insects and related products in the future.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.8
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• pp.1220-1230
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• 2010

The purposes of this study were to compare price sensitivity analysis for using environmental-friendly agricultural products in university foodservice between Jeonnam and Gyeongnam areas in Korea and to suggest the optimum guideline for price increase. The questionnaires were distributed to 600 university students respectively in Jeonnam and Gyeongnam area from July 15 to July 25, 2008; among them, 570 students from Jeonnam area and 490 students from Gyeongnam area responded. The results of this study were as follows. First, Indifference price (IDP) were 890 won (Jeonnam area) and 1,050 won (Gyeongnam area); Optimum price point (OPP) were 1,030 won (Jeonnam area) and 1450 won (Gyeongnam area). Price stress range were 140 won (890~1030 won) in Jeonnam area and 400 won (1050~1450 won) in Gyeongnam area. Second, point of marginal cheapness (PMC) were 500 won (Jeonnam area) and 790 won (Gyeongnam area) whereas point of marginal expensiveness (PME) were 1,170 won (Jeonnam area) and 1820 won (Gyeongnam area). Range of acceptable price (RAP) were 670 won (500~1170 won) in Jeonnam area and 1030 won (790~1820 won) in Gyeongnam area. Third, on the basis of IDP percentage and RAP, students in Jeonnam area were more sensitive to meal price increase than students in Gyeongnam area. In contrast, on the basis of Price Stress, students in Gyeongnam area were more sensitive to meal price increase than students in Jeonnam area. Hence, when using environmental-friendly agricultural products in university foodservice, in Jeonnam area, meal price increase should be recommended to be in RAP (500~1170 won), and in Gyeongnam area, meal price increase should be recommended to be in RAP (790~1820 won).