• Communications of Mathematical Education
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• v.28 no.2
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• pp.255-279
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• 2014

This study is to investigate the change of intelligent and affective domains through the student self-evaluation to identify causes of wrong answers. Through this evaluation, students could have opportunities to solve the given mathematical problems basically and to reflect their problem-solving process, and further to recognize which mathematical content(concepts or expressions, symbols, etc.) led them to solve the problems incorrectly or wrong. Through this process, they would correct their wrong process and answers and to reinforce the prerequisite knowledges relevant to the problems, and furthermore, to enhance problem-solving abilities. To accomplish this, this study was executed as a case study on the subject of four tenth graders. The subject consisted of two boys and two girls. In this study, three essay types of mathematical problems in tenth grade level were chosen from several domestic tests in Korea. Based on the original three essay type of problems, three types of similar problems, namely equivalent problem, similar problem, and isomorphic problems were reconstructed, respectively by the researchers. The subjects were guided to solve the original three problems, and they corrected their wrong parts of the first problem of the three problems. They solved an equivalent problem of the first problem and executed self evaluation and also corrected wrong parts. Next, they dealt with a similar problem of the first problem and executed self evaluation and also corrected wrong parts. Next, while dealing with an isomorphic problem of the first problem, the subjects did the same things. Thus, for the second and third original problems, the study was implemented in the same way. To explore their intelligent and affective domains through student self-evaluation in-depth, the subjects were interviewed formally before and after conducting the experiment and interviewed informally two times, and the recordings were audio-typed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.5
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• pp.391-399
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• 2020

KASI (Korea Astronomy and Space Science Institute) has been developing the multipurpose laser tracking system with three functions of satellite laser tracking, adaptive optics and space debris laser tracking for scientific research and national space missions. The space debris laser tracking system provides the distance to space debris without a laser retro-reflector array by using a high power pulse laser, which employs a spinning disk to change the optical path between the transmit and receive beams. The spinning disk causes the collision band which is unable to reflect the returned signal to a detector and then has an effect on the tracking coverage of space debris. This study proposed the mathematical model for tracking coverage by taking into account the various specifications of spinning disk such as disk size, spinning velocity and collision rate between the disk and hole. In addition, the spinning disk specifications were analyzed in terms of tracking coverage and collision band based on the mathematical model to investigate tracking requirements of the Geochang laser tracking system.

• Journal of Food Hygiene and Safety
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• v.26 no.3
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• pp.222-226
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• 2011

Salmonellosis is a major bacterial zoonosis that causes self-limited enteritis to fatal infection in animals and food-borne infection and typhoid fever in humans. Multidrug-resistant strains of Salmonella spp. has increased over the last several decades and recently causes more serious problems in public health. The present study was investigated bacteriocidal effects of sodium chlorate, sodium azide, sodium cyanide, and sodium salts mixture containing sodium chlorate, sodium azide, and sodium cyanide on infection with S. typhimurium in macrophage RAW 264.7 cells, and antibacterial effects of sodium salts mixture for murine salmonellosis. In infection assay of S. typhimurium in RAW 264.7 cells, bacterial survival rates within macrophage in all treated groups was significantly reduced comparing to that of the control group with the passage of incubation time. Administration of sodium salts mixture showed a therapeutic effect for S. typhimurium infected ICR mice. The mortality of mice treated with sodium salts mixture was 70% until 12 days, while that of control mice was 100% until 9 days after S. typhimurium infection. The results of this study strongly indicate that sodium salts mixture has a potency treatment for murine salmonellosis.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.1
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• pp.31-38
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• 2012

The geo-referencing accuracy of the images acquired by a UAV based multi-sensor system is affected by the accuracy of the mounting parameters involving the relationship between a camera and a GPS/INS system as well as the performance of a GPS/INS system. Therefore, the estimation of the accurate mounting parameters of a multi-sensor system is important. Currently, we are developing a low altitude multi-sensor system based on a UAV, which can monitor target areas in real time for rapid responses for emergency situations such as natural disasters and accidents. In this study, we suggest a system calibration method for the estimation of the mounting parameters of a multi-sensor system like our system. We also generate simulation data with the sensor specifications of our system, and derive an effective flight configuration and the number of ground control points for accurate and efficient system calibration by applying the proposed method to the simulated data. The experimental results indicate that the proposed method can estimate accurate mounting parameters using over five ground control points and flight configuration composed of six strips. In the near future, we plan to estimate mounting parameters of our system using the proposed method and evaluate the geo-referencing accuracy of the acquired sensory data.

• Clinics in Shoulder and Elbow
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• v.11 no.2
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• pp.158-164
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• 2008

Purpose: We compared the results of arthroscopic Bankart repair using metal and biodegradable anchor fixation. Materials & Methods: We reviewed 26 patients with anterior shoulder instability treated by arthroscopic Bankart repair from October, 2006, to March, 2007, 15 patients with metal anchors and 11 patients with biodegradable anchors. The average age was 27.4 years old (range: 17~55) and mean follow-up was 14 months (range: 12~17 months). Functional outcome was evaluated using the Korean Shoulder Score for Instability (KSSI), Rowe's Bankart Grading scale (RBGS), ASES score, and UCLA scores. Results: In the metal-anchor group, the improvements of mean KSSI, ASES, UCLA score, and RBGS were 20.6, 24.0, 4.0, and 45.5, respectively. In the biodegradable anchor group, improvements of mean KSSI, ASES, UCLA score, and RBGS were 21.0, 23.6, 4.6, and 48.9. The improvements in final outcomes were not significantly different (p>.05). One metal problem and one traumatic redislocation occurred in the metal group. Conclusion: Both techniques produced satisfactory outcomes in the treatment of traumatic anterior instability. The biodegradable anchor group could also avoid problems with metal anchors.

• Korean Journal of Food Science and Technology
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• v.39 no.2
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• pp.152-157
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• 2007

In an attempt to develop functional salts having beneficial health effects, we experimentally prepared three functional salts by fortification with soluble seaweed minerals (Hizikia mineral salt, HMS), fucoidan (fucoidan salt, FS) and laver extracts (laver salt, LS). To characterize the functional salts, their physicochemical properties and in vitro functionalities, such as pH, color, mineral composition, solubility, oxidation-reduction potential, sensory properties, angiotesin converting enzyme (ACE) inhibitory activity, and bile acid binding capacity were investigated. The functional salts revealed slightly lower NaCl concentrations, but showed a variety of pH values compared with conventional table salt. The pH values of HMS, FS, and LS were 11.3, 6.8, and 6.5, respectively. The oxidation-reduction potentials (ORP) of the functional salts varied from -229 mV to 38 mV, significantly lower than refined salt. The functional salts were significantly darker in color than refined salt, and the mineral composition of HMS was considerably enriched compared to refined salt, particularly in potassium ion. As a result of the sensory evaluation, FS and LS were comparatively palatable in saltiness, pungency, bitterness, and overall acceptance compared with refined salt. It was also found that one functional salt had ACE inhibitory activity (54.8% in LS) and another had bile acid binding capacity (80.7% in FS).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.04a
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• pp.235-239
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• 1996

분류가 모서리에 충돌할 때 발생하는 순음성 소리인 쐐기소리(edgetone)는 공력음향의 대표적인 현상으로서 지금까지 수많은 연구가 있어 왔으며 그 대부분의 특성이 규명되었다고 할 수 있다. 쐐기소리의 발생기구인 되먹임(feedback) 이론을 처음으로 제안한 이는 Powell로서 그는 되먹임사이클의 위상조건에 의하여 주파수특성에 관한 모델을 제안하였으며, 최근 그 모델의 위상인자에 관하여 Kwon은 새로운 값을 제안한 바 있다. 그런데, 쐐기소리의 이론은 주로 분류가 쐐기나 벽에 충돌할 경우에 집중되어 왔으며 분류가 원통에 충돌하여 발생하는 경우에 관한 연구는 Krothapalli의 초음속분류에 관한 연구와 Mochizuki등의 아음속분류에서 원통지름의 영향에 관한 연구를 들 수 있을 뿐이다. Mochizuki등은 원통의 지름이 노즐의 높이보다 작은 경우에 쐐기 소리의 주파수가 원통의 와류이탈(vortex shedding) 주파수와 같은 것을 관찰하였다. 그러나 분류와 원통이 작용하여 발생하는 쐐기소리의 주파수 특성에 관한 이론적 해석을 시도한 연구는 없으며 또한 방사음장의 특성에 관하여도 Han과 Kwon에 의한 모델이 발표된 바 있으나 실험적으로 입증되지 못하였다. 따라서, 본 연구의 목적은 2 fig.1과 같이 2차원 분류가 원통에 충돌할 때 발생하는 쐐기소리의 주파수특성의 정량적인 모델을 세우고 방사음장의 지향특성의 이론 모델을 확립하는 것이다. 먼저 주파수특성을 실험하고 되먹임이론을 적용하여 분석하므로써 유효음원의 위치를 구하고 또한, 수직벽에 작용하여 발생하는 충돌음(impinging tone)의 경우를 실험하여 주파수특성을 비교 고찰하므로써 유효음원의 위치에 관한 이론을 입증한다. 아울러 원통과 평면벽의 각 경우에 방사음장의 지향특성을 측정하고 고찰한다.2,5,6]을 단계별로 고찰하여, 점점 까다로워져 가는 선박 진동규제[3,4]에 대처하고 승무원의 안락성에 대한 욕구, 구조물의 안전성, 장비의 성능보존이 만족되는 저진동 선박의 건조를 위해 향후 해결해야할 과제들을 도출하여 선박진동분야이 연구개발 방향을 제시하고자 한다. 하는 것은 진단의 정밀도에 문제가 있을 것으로 생각된다. 따라서 언어적진리치가 도입되어 [상당히 확실], [확실], [약간 확실] 등의 언어적인 표현을 이용하여 애매성을 표현하게 되었다. 본 논문에서는 간이진단 결과로부터 추출된 애매한 진단결과중에서 가장 가능성이 높은 이상원인을 복수로 선정하고, 여러 종류의 수치화할 수 없는 언어적(linguistic)인 정보ㄷㄹ을 if-then 형식의 퍼지추론으로 종합하는 회전기계의 이상진단을 위한 정밀진단 알고리즘을 제안하고 그 유용성을 검토한다. 존재하여도 모우드 변수들을 항상 정확하게 구할 수 있으며, 또한 알고리즘의 안정성이 보장된 것이다.. 여기서는 실험실 수준의 평 판모델을 제작하고 실제 현장에서 이루어질 수 있는 진동제어 구조물에 대 한 동적실험 및 FRS를 수행하는 과정과 동일하게 따름으로써 실제 발생할 수 있는 오차나 error를 실험실내의 차원에서 파악하여 진동원을 있는 구조 물에 대한 진동제어기술을 보유하고자 한다. 이용한 해마의 부피측정은 해마경화증 환자의 진단에 있어 육안적인 MR 진단이 어려운 제한된 경우에만 실제적 도움을 줄 수 있는 보조적인 방법으로 생각된다.ofile whereas relaxivity at high field is not affected by τS. On the other hand, the change in τV does not affect low field profile but strongly in fluences on both

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1991.04a
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• pp.75-79
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• 1991

고도로 산업화가 진행됨에 따라 회전기계는 더욱 중요시되고 있으며 이의 성능 향상에 부단한 노력이 경주되고 있다. 특히 우주 시대의 개막과 더불어 우주선 및 인공위성에 사용하기 위해 초소형이며 초고속의 고성능회전모타 를 개발하기에 이르렀다. 한 예로서 미국립항공우주국(NASA)의 스페이스셔 틀에 사용되는 주엔진 터보펌프를 들 수 있는데 이 터보펌프는 접시만한 크 기로써 71000마력을 생성해 낸다. 이러한 가공할 만한 에너지 밀도와 유량을 감당해 내려면 종래의 회전기계보다는 훨씬 더 높은 회전속도를 가져야 한 다. 이러한 회전체는 큰 관성부하와 진 동 및 동안정성의 문제등을 내포하고 있다. 고성능 회전기계의 또다른 예로서 초정밀 가공용 공작기계를 들 수 있 다. 선반 혹은 밀링머신으로 초정밀가공을 행하기 위해서는 회전축의 진동이 극히 작아야 한다. 이와 같이 오늘날 갈수록 초고성능 초정밀도를 추구함에 있어서 회전축의 진동을 현장에서 모니터링하고 이 진동데이터를 분석하여 회전축을 제어하는 것이 강력히 요구되어진다. 따라서 in-situ 측정이 중요성 을 띠게 되었는데 이는 제어기술의 바탕이 되는 자료를 현장에서 제공할 수 있기 때문이다. 회전축 진동측정의 대상이 되는 것들은 모타, 발전기, 엔진 및 터빈등을 대표적으로 들 수가 있다. 여기서 소형회전기계의 축표면과 같 이 비교적 곡면을 이루고 있는 부분의 진동변위 측정에 신중한 고려가 요구 되어 진다. 이는 축의 곡면도에 따라 감도가 변화하기 때문이다. 따라서 평 판에 대한 calibration 챠트를 회전기계축진동 변위환상에 이용하면 곡률에 따라서 오차가 생기게 된다. 본 연구에서는 비접촉 축진동측정시 발생되는 오차에 대하여 검토하고자 한다. from the studies, the origin of ${\alpha}$$_1$peak was attributed to the detrapping process form trap with 2.88[eV] deep of injected space charge from the chathode in the crystaline regions. The origin of ${\alpha}$$_2$ peak was regarded as the detrapping process of ions trapped with 0.9[eV] deep originated from impurity-ion remained in the specimen during production process of the material, in the crystalline regions. The origin of ${\beta}$ peak was concluded to be due to the depolarization process of "C=0"dipole with the activation energy of 0.75[eV] in the amorphous regions. The origin of ${\gamma}$ peak was responsible to the process combined with the depolarization of "CH$_3$", chain segment, with the activation energy of carriers from the shallow trap with 0.

• Korean Journal of Poultry Science
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• v.10 no.2
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• pp.113-121
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• 1983

In an effort to understand epizootiological aspects of infectious laryngotracheitis (ILT), a total of 56 chicken flocks in six farms comprised of 35 broiler breeder, 13 commercial layer and 6 layer breeder flocks. were investigated. The farms experienced ILT during the period of one year from June, 1982. In most farms the birds were vaccinated against ILT just before or after the disease outbreak. In two of the farms in which ILT broke out in winter, it was possible to contain the disease in only one or two fleets without transmitting it to the remaining 5 to 7 flocks in the farms by adopting strict isolation procedures for the affected flocks. In regarding inter- flock spreading speed, it took an average of 6 days for flocks rearing on floor and 11 days for those in cages. Among the flecks in rearing cages. transmission among laying flocks was much faster. taking an average of 8 days, compared to non-laying flocks of 17 days, suggesting spreading of the disease by means of egg trays or egg collection process. Peak mortality was observed between 5 and 10 days after from the time of appearance of first dead birds from the disease and the period of mortality, with an average of 18 days, was not influenced by rearing systems, breeds and age of birds. Mortalities in the affected flocks ranged from lo/e to 19.8%, with an average of 6.5 %, and was also not influenced by the above variables except significantly lower mortality in immature broiler breeder flocks (2.9%) compared to immature layer (11.8%) and mature broiler breeder flocks (6.9%). In one breeder farm in which all the birds were kept on floor and ILT broke out in summer, mortality in male birds in all seven flocks of 37 weeks of age or older was as high as twice of that in female birds in the same flocks. This trend was not observed in one 31 weeks old flock and was reversed in another 14 weeks old flock in the farm.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.2
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• pp.195-202
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• 1983

Sixty paddy soil samples were collected from the different Korean agricultural climatic area to find relationship between soil physicochemical properties and soil microorganisms. The results are summarized as follows : 1. The mean numbers of microorganisms in collected paddy soils were $121.8{\times}10^5$ in bacteria (B), $22.5{\times}10^5$ in actinomycetes (A) and $32.4{\times}10^3$ in fungi (F) per gr soil. The ratios of B/F, B/A, and A/F were 385, 5.1 and 82, respectively. 2. Number of soil microorganism was lowest in Mountainous area, lower in Eastern Coast, Gyeonggi Bay and Chungcheong Continental area, but higher in Honam Plain and Southern Part. 3. The significant positive correlation were obtained between the number of microorganisms and soil chemical properties, available phosphorous, $K^+$, $Mg^{++}$, T-C and soil pH. 4. The number of soil microorganism was in the order of Clay loamy soil > Clayey soil > Loamy soil > Sandy loamy soil.