• Journal of Gifted/Talented Education
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• v.26 no.2
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• pp.405-421
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• 2016

The purpose of this study was to investigate students' perception of Advanced Placement Program. Participations of this study were 1144 students from 14 science high schools. The results showed as follows. First, students perceived positively regarding AP program and were willing to take AP courses because of interesting and challenging in academic area which is provided by AP courses. Secondly, many students would like to take AP courses in Differential and Integral Calculus 1, General Physics I, General Chemistry I and General Biology. Also, they would like to take AP courses in first term as a mandatory subjects. Third, responses perceived that AP courses were challenging, difficult, and of high quality. Finally, students perceived the benefit of AP courses in earing college credit. However, 35% of responses wished to receive an exemption for all AP courses. Also, they wished to have dual-major or participate in students exchange program as a benefit of AP program. Implications of the study were discussed in depth based on the results.

• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.377-381
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• 2011

The purpose of this study is an assessment between the measured value of the nanoDot dosimeter and the calculated value of Non Dosimeter Dosimetry-Method(NDD-M) for entrance surface dose in general radiography. Measurement and calculation of the entrance surface doses were performed for head(AP), abdomen(AP), pelvis(AP), thoracic spine(AP) and lumbar spine(AP). As a result, the relative ratios of the measured value to the calculated value were acquired 1.5-2.1 for each region. Reproducibility acquired 0.035 as a coefficient of variation.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.581-583
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• 2011

최근에 급격히 증가한 스마트폰의 사용자들이 이동중에도 안정적인 무선 네트워크를 이용하기 위해서는 핸드오프는 반드시 필요하다. 핸드오프를 위하여 기존에 연결되어 있는 AP(Access Point)와의 연결을 끊고 주변의 AP 를 스캐닝한 후 새로운 AP 로 재연결을 하는 과정을 거치게 된다. 이러한 과정 중에 본 논문에서는 스캐닝 단계에서 발생하는 문제점을 분석하고 이에 대한 개선방안으로 AP 의 신호세기와 스마트폰의 센서를 이용하여 사용자의 이동성을 고려하는 스캐닝 방식을 제안한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.1
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• pp.87-95
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• 2014

Under only authorized AP is allowable environment, rogue AP which is generated by a smartphone tethering can be a serious security breach. To solve rogue AP problem, this paper proposes classifying algorithm of Kernel Support Vector Machine using features of RTT data. Through our experiment, we can detect rogue AP from LTE mobile network.

• Journal of Digital Contents Society
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• v.19 no.8
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• pp.1545-1554
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• 2018

In order to support the mobility of the wireless devices, at least two APs (Access Points) must be arranged in a single AP area to maintain communication area. In the WLAN (Wireless LAN) environment, seamless handover is one of the most important issues in terms of effective utilization of wireless networks and maximization of services for users. On the other hand, SDN (Software-Defined Networking), which is emerging rapidly in recent years, is revolutionizing network management in terms of flexibility, fine control, and convenience. SDN originally reduces latency time or increases network robustness by real-time flow table control reducing or bypassing paths between switches in LAN-based data centers. In this study, we apply OpenFlow, a SDN platform focused on wired LAN, to a dense WLAN environment using legacy APs to implement and evaluate seamless handover for streaming services of digital contents.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11c
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• pp.2329-2332
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• 2002

G-machine은 지연 함수형 언어를 효율적으로 구현하기 위한 추상기계이다. G-machine은 축약 과정에서 생성되는 그래프를 저장하기 위해서 많은 기억장소를 필요로 한다. 본 논문은 힙에 할당되는 그래프 노드 중 AP 노드를 재사용하는 방법을 제시한다. 일반적으로 AP 노드를 루트로 하는 그래프가 한 단계 축약된 후 다시 AP 노드를 루트로 하는 그래프로 구성되어지는 경우 루트 노드를 재사용할 수 있다. 이를 위해서는 기존 G-machine을 약간 확장 시켜야 하는데, 본 논문에서는 AP 노드의 일부를 변경하기 위한 명령어 UPDL과 UPDR을 제시하고, 이들 명령어의 상태변환 규칙과 이들 명령어 생성을 위해 수정된 R-변환 규칙을 제시한다. 본 논문에서 제시하는 방식으로 기 생성된 AP 노드를 재사용함으로써 힙 기억공간의 사용량을 줄일 수 있고, 이 과정에서 힙 기억장소 할당과 쓰기 연산의 수를 줄일 수 있다.

• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.807-812
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• 2018

In this study, we investigated the conditions used in setting the recommendation level of general radiography diagnostic reference and tried to evaluate the effective dose and biological evaluation using PCXMC v2.0 program. As a result based on the effective dose of male in ICRP 60, the highest Pelvis AP was 0.794 mSv. The lowest Chest PA was 0.050 mSv. In the case of ICRP 103, the highest T-Spine AP was 0.906 mSv The lowest Chest PA was 0.052 mSv. For 40 years old male and female adults, effective doses of general radiography were evaluated and even if the medical exposures are not subject to the limit of dose, efforts should be made to reduce the medical exposures of the people by keeping the dose below the recommended amount in order to minimize the probable effect of radiation hazard.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.7
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• pp.576-584
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• 2016

In this study, AP added propellant has been proposed as a method of enhancing the low specific impulse performance found for staged hybrid rocket engine. Experimental tests were carried out to analyze and evaluate the effect of AP added propellant on specific impulse performance as well as fuel-rich combustion characteristics in a staged hybrid rocket engine. Upper limit of AP content in propellant was set to be 15 wt% to maintain the hybrid rocket engine advantages. As a result, 15 wt% AP added propellant showed 3% higher specific impulse performance compared to 0 wt% AP added propellant. Moreover, AP addition proved to offer less injected oxidizer mass flow, less O/F variation, and less combustion pressure while producing fuel-rich gas of the same combustion temperature. Future studies will carry out more combustion tests with metal additives to further enhance specific impulse.

• Journal of the Korean Society of Radiology
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• v.7 no.3
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• pp.233-238
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• 2013

Chest lateral decubitus radiation exposure PA be carried out in general, but emergency patient or the patient's discomfort in the body examination had a lot of inconvenience. In this study, we compared AP and PA image quality, patient safety, and analysis of the examination effectiveness between the two tests was to evaluate the usefulness. Pleurisy or pneumothorax in patients with suspected or diagnosed chest lateral decubitus radiation exposure 30 consecutive patients (male 20 patients, 10 females) were included in the study. Image quality evaluation method microstructure of lung, wide areas of diagnosis, a clear air-fluid interface, the patient rotate, cardiac shadow and sharp diaphragmatic was based on Department of Radiology specialist, division of pulmonology resident blind test was evaluated by four people. Chest decubitus by radiation exposure the AP and PA position examination the usefulness of comparative analysis Image quality in the AP and PA, whereas there was no significant difference in attitude, Stability of the patient and Radiation's examination efficiency AP position compared to the position of PA scores were higher. PA position does not require a examination may be of AP position in a position to suggest that.

• International Journal of Highway Engineering
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• v.2 no.1
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• pp.123-133
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• 2000

The asphalt mixture with CRM(Crumb Rubber Modifier) is known to show a better performance in resisting thermal cracking, fatigue cracking, and rutting compared with the conventional mixture. In this research, the lab tests on the physical and the mechanical characteristics of the domestic crumb rubber modified asphalt binder and conventional asphalts (AP-3, AP-5) were conducted. The physical test results show that CRM asphalt has better physical characteristics than that of conventional asphalts. The dynamic shear rheometer test results in high temperature show that CRM asphalt has higher complex shear modulus and aging resistance than those of conventional asphalts. And, the bending beam rheometer in low temperature test results show that CRM asphalt has higher resistance to thermal cracking than that of conventional asphalts.