• 한국과학교육학회지
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• 제24권4호
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• pp.687-708
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• 2004

The purpose of this study is to investigate the relationships between cognitive conflict and students' causal attributions and to find out what kinds of attributions affect successful resolution of cognitive conflict in learning physics. Twenty-nine college students who attended a base general physics course took an attribution test and a conceptual pretest related to action and reaction concept. Of these, twenty students who revealed alternative conceptions were selected. They were confronted with a discrepant demonstration and took part in the cognitive conflict level test, a posttest, and delayed posttest. Those students who experienced high levels of cognitive conflict were selected and interviewed to find out what kinds of attributions affect resolving the conflict. When confronted with the discrepant event, the students who attributed success outcomes to "effort" experienced higher levels of cognitive conflict than those to "task difficulty." However, those students who revealed high levels of cognitive conflict and attributed success outcomes to effort did not always produce conceptual change. They had different perspectives on effort and conducted different effort activities to resolve the cognitive conflict. In addition, these effort activities appeared to include their motivational beliefs, metacognitive and volitional strategies. The results of this study indicate that in order for the conflicts to lead to change, students need to have the perspective on effort implying the use of the self-regulated learning strategy and to conduct effort activities based on them. Beyond cold conceptual change, this article suggests that there is a management strategy of cognitive conflict in the classroom context.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.77-81
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• 2004

In this paper, we propose a analog front-end (AFE) for noncoherent On-Off Keying (OOK) Ultra Wide Band (UWB) system based on power detection. The proposed AFE are designed using 0.18 micron CMOS technology and verified by simulation using SPICE. The proposed AFE consist of Sample-and-Hold block, Analog-to-Digital converter, synchronizer, delayed clock generator and impulse generator. The time resolution of 1ns is obtained with 100MHz system clocks and the synchronized 10-bit digital outputs are delivered to the baseband. The impulse generator produces 1ns width pulse using digital CMOS gates. The simulation results show the feasibility of the proposed UWB AFE systems.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1081-1085
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• 2009

We have already developed EMI reducing techniques using lossless compression by vertically differential EMI suppression method (VDE[1]). It applies lossless modulo reduction and data bit mapping optimization for low voltage differential signaling (LVDS) transmission lines, that reduces the probability of transient bit and EMI by 12 dB [6][7]. We also improved and optimized the VDE for low power LCD interface. With this modified VDE algorithm[8], the developed FPGA was measured the reduction of the power consumption of LCD circuit by more than 15 % compared to the conventional methods in the case of 14-in LCD with SXGA resolution. The VDE algorithm is based on the total image systematic approach. In the VDE method, the present image signals are subtracted for the 1H delayed image signals and transferred to a column driver through a PCB. As the vertical correlations for image signals are very high, we expected that most of the vertically subtracted image signals remain 0 level and transient cycles become very long. As a result, the power consumption and EMI are extremely reduced for the transferred image signals on a PCB. In this paper, we discussed our proposed method by emphasizing the fact that systematic approach are important based on not only display point of view but also total system point of view.

• Parasites, Hosts and Diseases
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• 제51권1호
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• pp.69-74
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• 2013

Leishmania tropica is one of the causative agents of leishmaniasis in humans. Routes of infection have been reported to be an important variable for some species of Leishmania parasites. The role of this variable is not clear for L. tropica infection. The aim of this study was to explore the effects of route of L. tropica infection on the disease outcome and immunologic parameters in BALB/c mice. Two routes were used; subcutaneous in the footpad and intradermal in the ear. Mice were challenged by Leishmani major, after establishment of the L. tropica infection, to evaluate the level of protective immunity. Immune responses were assayed at week 1 and week 4 after challenge. The subcutaneous route in the footpad in comparison to the intradermal route in the ear induced significantly more protective immunity against L. major challenge, including higher delayed-type hypersensitivity responses, more rapid lesion resolution, lower parasite loads, and lower levels of IL-10. Our data showed that the route of infection in BALB/c model of L. tropica infection is an important variable and should be considered in developing an appropriate experimental model for L. tropica infections.

• 대한핵의학회지
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• 제39권3호
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• pp.151-162
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• 2005

Hemangioma is the most common benign tumor of the liver, with a prevalence estimated as high as 7%. Tc-99m red blood cell (RBC) hepatic blood pool scan with single photon omission computed tomography (SPECT) imaging is extremely useful for the confirmation or exclusion of hepatic hemangiomas. The classic finding of absent or decreased perfusion and increased blood pooling ("perfusion/blood pool mismatch") is the key diagnostic element in the diagnosis of hemangiomas. The combination of early arterial flow and delayed blood pooling ("perfusion/blood pool match") is shown uncommonly. In giant hemangioma, filling with radioactivity appears first in the periphery, with progressive central fill-in on sequential RBC blood pool scan. However, the reverse filling pattern, which begins first in the center with progressive peripheral filling, is also rarely seen. Studies with false-positive blood pooling have been reported infrequently in nonhemangiomas, including hemangiosarcoma, hepatocellular carcinoma, hepatic adenoma, and metastatic carcinomas (adenocarcinoma of the colon, small cell carcinoma of the lung, neruroendocrine carcinoma). False-negative results have been also reported rarely except for small hemagniomas that are below the limits of spatial resolution of gamma camera.

• Journal of Gastric Cancer
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• 제19권3호
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• pp.365-371
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• 2019

The role of surgical intervention in patients with diabetic gastroparesis is unclear. We report a case of a 37-year-old man with a history of recurrent episodes of vomiting and long-standing type 2 diabetes mellitus. Esophagogastroduodenoscopy did not reveal any findings of reflux esophagitis or obstructive lesions. A gastric emptying time scan showed prolonged gastric emptying half-time (344 minutes) indicating delayed gastric emptying. Laboratory tests revealed elevated fasting serum glucose and glycosylated hemoglobin (HbA1c, 12.9%) and normal fasting C-peptide and insulin levels. We performed Roux-en-Y reconstruction after subtotal gastrectomy to treat gastroparesis and improve glycemic control, and the patient showed complete resolution of gastrointestinal symptoms postoperatively. Barium swallow test and gastric emptying time scan performed at follow-up revealed regular progression of barium and normal gastric emptying. Three months postoperatively, his fasting serum glucose level was within normal limits without the administration of insulin or oral antidiabetic drugs with a reduced HbA1c level (6.9%). Long-limb Roux-en-Y reconstruction after subtotal gastrectomy may be useful to treat severe diabetic gastroparesis by improving gastric emptying and glycemic control.

• Clinical and Experimental Pediatrics
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• 제50권3호
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• pp.241-247
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• 2007

목 적 : 선천성 근성 사경은 목빗근의 섬유화 변화로 인해 머리가 병변쪽으로 기울고 턱이 반대쪽으로 돌아가는 변형을 말하는 것으로 대개 생후 4주내에 발견되고 생후 수개월내에 소실되는 예후가 좋은 질환이다. 이와 관련된 국내 보고가 부족하나 비교적 흔한 근골격계 기형이기에 저자들은 연구를 시행하였다. 방 법 : 2003년 3월부터 2006년 5월까지 본원 소아과와 재활의학과에 사경을 주소로 내원한 환아 중 안과적 검사, 신경학적 진찰 및 정형외과적 진찰 소견에서 이상이 없는 선천성 근성 사경 환아 47명을 대상으로 하였다(남자 31명, 여자 16명). 임상적 특성으로 발견 당시의 연령, 진찰 소견, 초음파 검사, 치료 방법, 치료 기간, 치료 결과 등을 조사하였다. 결 과 : 진단 당시의 연령은 최소 18일에서 최고 9세 7개월로, 이들 연령의 중앙값은 90일이었고, 좌우측 발생 빈도는 우측이 26명, 좌측이 21명이었다. 진찰 소견상 경부 종괴가 만져지는 군은 24명으로 이 중 21명에서 초음파가 시행되었고 19명에서 초음파상 목빗근의 종괴가 관찰되었다. 진찰 소견상 정상적이었던 환아는 22명으로 이 중 11명에서 초음파가 시행되었으며, 3명에서 초음파상 목빗근의 종괴가 관찰되었다. 진단 당시 가장 나이가 많았던 환아는 수술로서 회복되었고, 그 외의 환아들은 모두 집이나 병원에서 수동적인 신연 운동을 받았다. 총 47명의 환아 중 7명이 추적관찰에서 누락되었고, 추적 관찰된 40명 중 36명은 완전한 회복을 보였다. 환아들의 진단 당시 연령과 회복 기간은 음의 상관관계를 가졌고, 초음파 소견에 따라 분류하였을 때 자세군에서는 85.7%, 종괴군에서는 90.0%, 근성군에서는 66.6 %의 완전한 회복을 보였다. 회복 기간은 자세군은 1개월, 종괴군은 2.4개월, 근성군은 7.5개월로 자세군에서 회복 기간이 가장 짧았다(P=0.0011). 결 론 : 초음파에서 목빗근의 이상 소견을 보였던 환아에서 더 느리게 호전되는 양상을 보이고 초음파 소견에 따라 서로 다른 치료 효과를 보였기에, 치료 효과와 기간을 예측하는데 초음파 소견이 도움이 될 것으로 생각된다.

• 한국음향학회지
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• 제41권3호
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• pp.268-277
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• 2022

본 논문에서는 KVLCC2 선체 축소모형에 설치된 추진시스템의 세부 구성품별 유동 소음원을 분석하였으며, 각각의 소음원이 수중방사소음에 미치는 영향에 대해 정량적으로 분석하였다. 수치 해석 영역은 실험 결과와의 비교를 위하여 선박해양플랜트연구소 대형 캐비테이션 터널의 시험부와 동일하게 설정하였다. 먼저 유동장내 소음원을 정확하게 모사하기 위하여 고정밀 해석기법인 비압축성 다상 Delayed Detached Eddy Simulation 방법을 적용하였고, 유동해석 결과를 기반으로 Ffowcs Williams and Hawkings 적분방정식을 사용하여 수중방사소음을 예측하였으며, 터널 실험결과와의 비교를 통해 해석절차의 유효성을 확인하였다. 추진시스템의 유동 소음원별 영향을 정량적으로 비교하기 위하여 추진기 날개 끝-와류 공동, 날개 표면 그리고 방향타 표면을 소음원 영역으로 선정하였으며, 음압과 파워 스펙트럼 밀도, 음향 파워를 비교하였다. 공동에 의한 홀극 소음원의 기여도가 추진기 날개 및 방향타에 의한 쌍극 소음원에 비해 수중방사소음에 크게 기여하였으며, 추진기 후류의 영향으로 방향타에 의한 기여도가 추진기 보다 더 크게 발생함을 확인하였다.

• 한국농림기상학회지
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• 제25권4호
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• pp.284-301
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• 2023

본 연구에서는 1km 고해상도 앙상블 신기후변화 시나리오(공통사회 경제경로 시나리오) 자료를 기반으로 하여 남한을 포함한 한반도 전체의 벼 기후생산성(CYP) 변화를 평가하였다. 이때, 기후변화 시나리오자료에서 제공하는 제한적인 변수를 활용하기 위해 일조시간을 대신하여 일사량을 이용하였다. 연구 결과에 따르면, 현재 기후에 비해 온난화된 미래 기후조건에서 CYPmax 값은 감소하고 최적출수일은 점차 늦춰지는 경향이 나타났다. 이는 고도가 높은 한반도 북동부의 산악 지역을 제외하고 모든 지역에서 나타나는 현상이며, 특히 온난화가 빠르게 진행되는 SSP585시나리오 일수록 더욱 뚜렷하게 나타났다. 이러한 결과는 낮은 배출 시나리오의 이점을 보여주는 동시에 온실 가스 배출을 제한하기 위해 더 많은 노력을 기울일 필요가 있음을 강조한다. 한편, CYPmax의 시계열에서 넓은 폭의 앙상블 스프레드가 나타났는데, 이는 단일모형 혹은 작은 수의 모형을 선택하였을 때 미래 변화 분석에 내재된 불확실성을 보여주며 앙상블 예측의 중요성을 보여준다. 본 연구를 통해 분석된 장기간의 기온 및 일사 조건의 변화에 따른 기후학적 벼 생산성 변화 및 불확실성에 대한 분석은 기후변화 대응을 위한 기초정보로써 가치가 있다.

• 농촌의학ㆍ지역보건
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• 제20권2호
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• pp.169-174
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• 1995

The case was described of a 31 year old female who developed fusiform swelling of the right third finger at the site of puncture by sea urchin spine. We observed a radiopaque linear material suggesting a remnant spine which the size was 2.4 mm in sonography and mammography. We confirmed that it exhibits a urchin spine and distinct caseous necrosis with central calcification. Sea urchins(Echinoidea) are ubiquitous marine creatures that resemble pincushions and are covered by calcareous skeletons surrounded by numerous movable calcium carbonate spines. The sharp spines are brittle and easily detach when touched by the victim. Contact with sea urchin spines produces intense pain, some localized erythema and edema. Inflammation develops in response to retained fragments. Granulomas 1-5 mm in diameter develop rarely 2-12 months after envenomation. In treatment, hot water immersion and thorough wound cleansing are advisable. Analgesics may, be necessary after hot water immersion. Attempts to remove these spines should be performed with good lighting sources, preferably with radiological direction. Chronic granulomas usually require complete excision. Acetone has been suggested for rapid resolution of pain. No antidotes are available.