• 대한수학교육학회지:수학교육학연구
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• 제16권1호
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• pp.59-78
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• 2006

본 연구에서는 먼저, 미적분에서 수학과 물리를 연결한 학습-지도의 필요성을 논의하고, 이를 위한 교수-학습 자료를 개발하여 제시한다. 그 후, 교수-학습 자료 중 하나를 활용하여 질적 사례연구를 하여 등가속도 운동을 탐구하는 활동에서 평균속도와 순간속도 개념이 발달되는 과정을 분석하였다. 연구대상자들은 등가속도 운동을 탐구하는 물리적 실험 상황에서 평균속도, 순간속도, 가속도 개념을 배웠다. 이 과정에서 학생들은 순간속도가 시간과 이동거리의 이차함수 그래프 위의 한 점에서 접선의 기울기를 의미한다는 점과 시간과 속도의 관계그래프 아래의 넓이 변화율이 이동거리의 변화율을 의미한다는 점을 이해할 수 있었다.

• 한국콘텐츠학회논문지
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• 제7권10호
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• pp.135-145
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• 2007

하나 TV로 대표될 수 있는 TV 포털은 인터넷 종합 포털 미디어와 유사한 기능을 가지고 있을 뿐만아니라, 다운로드 파일 소비의 특성을 지니고 있다고 할 수 있다. 따라서, 이 연구에서는 하나 TV가 지니고 있는 TV포털로서의 특징이 콘텐츠 구성 및 실제 이용에 있어서 어떻게 전개되는지 살펴보고자 했다. 연구 대상은 하나 TV의 월간 접속률과 콘텐츠 요청 건수 등이며, 연구 방법으로는 기존 자료에 대한 2차 분석과 월간 시청 빈도와 콘텐츠 요청 건수에 대한 빈도 분석을 실시했다. 하나 TV의 콘텐츠 유형별 시청 빈도와 콘텐츠 요청 건수를 분석한 결과, 하나 TV시청자들이 현재 가장 많이 시청하고 있으며 향후에도 보기를 희망하는 콘텐츠 유형은 지상파 방송 프로그램인 것으로 나타났다. 이는 하나 TV가 지상파 방송의 보완 매체로 기능할 가능성이 높다는 것을 의미한다. 이에 따라 향후 케이블 TV 및 인터넷 '다시보기' 서비스와의 직접적인 경쟁이 예상된다.

• International Journal of Advanced Culture Technology
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• 제6권4호
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• pp.266-274
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• 2018

Securing field screens through LTE broadcasting is a very valuable technology in news production because of its locality and concurrency. TV has the advantage of being able to deliver news faster than newspapers and make live coverage on the scene of events and events. To maximize this, not only middle-end broadcasters but also existing broadcasting stations are taking an active role in broadcasting using LTE. However LTE broadcasting has yet to secure any conflicting values of broadcasting stability and securing high-definition. The key to solving this difficulty is the transmission rate of Bit Rate. This paper compares the Bit Rate transmission method, which is variable and fixed, to provide more on-site screens through LTE, and presents the Bit Rate adjustment method as a method of screen stabilization through experiment. Consequently, the most stable broadcast screen can be obtained when transmitting and connecting it to broadcasting in a variable 5M method.

• International Journal of Vascular Biomedical Engineering
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• 제1권2호
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• pp.20-29
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• 2003

A new treatment for coronary artery occlusive disease is being developed in which a shunt or conduit is placed directly connecting the left ventricle with the diseased artery at a point distal to the obstruction. To aid in assessing and optimizing its benefit, a computational model of the cardiovascular system was developed and used to explore various design conditions. Simulation results indicate that in complete LAD occlusion, flow can be returned to approximately 65% of normal if the conduit resistance is equal for forward and reverse flow, increasing to 80% in the limit in which backflow resistance is infinite. Increases in flow rate produced by asymmetric flow resistance are considerably enhanced in the case of a partial LAD obstruction since the primary effect of resistance asymmetry is to prevent leakage back into the ventricle("steal") during diastole. Increased arterial compliance has little effect on net flow with a symmetric shunt, but leads to considerable augmentation when the resistance is asymmetric. These results suggest that an LV-LAD conduit will be beneficial when stenosis resistance(Rst) > 27 PRU if resistance is symmetric.

• Tribology and Lubricants
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• 제16권6호
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• pp.461-468
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• 2000

In this study, a neural network based diagnostic system of a rotating spindle system supported by ball bearings was introduced. In order to create actual failure situations, two exemplary abnormal status were made. Out of several possible data source locations, ten measurement spots were chosen. In order to discriminate multiple abnormal status, a neural network system was introduced using back propagation algorithm updating connecting weight between each nodes. In order to find the optimal structure of the neural network system reducing the information sources, magnitude of the weight of the network was referred. Hinton diagram was used to visually inspect the least sensitive weight connecting between input and hidden layers. Number of input node was reduced from 10 to 7 and prediction rate was increased to 100%.

• Journal of Korean Neurosurgical Society
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• 제47권2호
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• pp.155-157
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• 2010

Anterior cranial fossa dural arteriovenous fistulae (DAVFs) are very rare and the bleeding rate is very high, especially in the presence of leptomeningeal draining vein and aneurysmal varix formation. A 85-year-old male patient presented with subdural hematoma (SDH). Magnetic resonance image (MRI) and transfemoral carotid angiography (TFCA) disclosed DAVF at the anterior cranial fossa with bilateral arterial feeders and leptomeningeal draining vein with varix formation. The lesion was treated by simple ligation of pial connecting vein using low frontal craniotomy. In comparison with DAVFs of the other sites, the anterior cranial fossa DAVF is difficult to manage by endovascular treatment due to not only the difficulty of transvenous access but the risk of visual impairment when using transarterial route. Surgical ligation of pial connecting vein is feasible and effective treatment.

• 항공우주정책ㆍ법학회지
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• 제22권2호
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• pp.85-108
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• 2007

동북아시아지역에서 인천국제공항이 최고의 허브공항으로서 역할을 위해서는 무엇보다도 환승율에 대한 연구가 필요하다고 판단된다. 인천국제공항은 2005년도에 3,054,485만명의 환승여객을 처리하여 환승율은 11.9% 를 기록하였는데 이는 동북아시아의 경쟁허브공항의 환승율인 30-40%와 비교해보면 공항경쟁력이 상당히 뒤쳐진다고 할 수 있다. 이러한 약점을 보완하기 위하여 여러 가지 관련 인자들을 검토하는 것이 중요하다고 판단되어지는데 그중에서 인천국제공항의 비행편최소연결시간(MCT)을 개선하는 것이 필요하다. 이러한 문제를 개선하기 위해서는 항공기 스케줄, 항공사 배치, 게이트 배정방법, 수하물처리, 여객 동선 등이 함께 검토되어야 할 것이다. 그러나 이러한 인자들에 대한 세부적인 분석이 단기간에 걸쳐 해결되는 문제가 아니기 때문에 본 연구에서는 외국 허브공항의 MCT 수준, 관리방법, 국외사례 등을 고찰해 보고 동북아시아에서 허브공항을 향한 인천국제공항의 환승율 제고차원에서 정책적 방안을 제시하고자 한다.

• Advances in nano research
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• 제15권2호
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• pp.155-163
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• 2023

Exercise is beneficial to the body in some ways. It is vital for people who have heart problems to perform exercise according to their condition. This paper describes how an Android platform can provide early warnings of fatigue during wushu exercise using Photoplethysmography (PPG) signals. Using the data from a micro-electro-mechanical system (MEMS) gyroscope to detect heart rate, this study contributes an algorithm to determine a user's fatigue during wushu exercise. It sends vibration messages to the user's smartphone device when the heart rate exceeds the limit or is too fast during exercise. The heart rate monitoring system in the app records heart rate data in real-time while exercising. A simple pulse sensor and Android app can be used to monitor heart rate. This plug-in sensor measures heart rate based on photoplethysmography (PPG) signals during exercise. Pulse sensors can be easily inserted into the fingertip of the user. An embedded microcontroller detects the heart rate by connecting a pulse sensor transmitted via Bluetooth to the smartphone. In order to measure the impact of physical activity on heart rate, Wushu System tests are conducted using various factors, such as age, exercise speed, and duration. During testing, the Android app was found to detect heart rate with an accuracy of 95.3% and to warn the user when their heart rate rises to an abnormal level.

• Journal of Mechanical Science and Technology
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• 제14권9호
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• pp.913-919
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• 2000

The purpose of this study was to develop a new element removal method for ESO (Evolutionary Structural Optimization), which is one of the topology optimization methods. ESO starts with the maximum allowable design space and the optimal topology emerges by a process of removal of lowly stressed elements. The element removal ratio of ESO is fixed throughout topology optimization at 1 or 2%. BESO (bidirectional ESO) starts with either the least number of elements connecting the loads to the supports, or an initial design domain that fits within the maximum allowable domain, and the optimal topology evolves by adding or subtracting elements. But the convergence rate of BESO is also very slow. In this paper, a new element removal method for ESO was developed for improvement of the convergence rate. Then it was applied to the same problems as those in papers published previously. From the results, it was verified that the convergence rate was significantly improved compared with ESO as well as BESO.

• Journal of Microbiology
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• 제42권3호
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• pp.200-204
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• 2004

Retron is a prokaryotic genetic element that produces multicopy single-stranded DNA covalently linked to RNA (msDNA) by a reverse transcriptase. It was found that cells producing a large amount of msDNA, rather than those that did not, showed a higher rate of mutation. In order to understand the molecular mechanism connecting msDNA production to the high mutation rate the protein patterns were compared by two dimensional gel electrophoresis. Ten proteins were found to be differentially expressed at levels more than three fold greater in cells with than without msDNA, nine of which were identified by MALDI TOF MS. Eight of the nine identified proteins were repressed in msDNA-producing cells and, surprisingly, most were proteins functioning in the dissimilation of various carbon sources. One protein was induced four fold greater in the msDNA producing cells and was identified as a 30S ribosomal protein S2 involved in the regulation of translation. The molecular mechanism underlying the elevated mutation in msDNA-producing cell still remains elusive.