• 대한지구과학교육학회지
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• 제7권1호
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• pp.43-53
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• 2014

이 연구의 목적은 계절의 변화 원인을 설명하는 과정에서 초등학생들의 개념 시뮬레이션을 분석함으로써 학생들이 어떻게 계절의 변화 원인에 대한 설명을 어떻게 생성하고 있는지를 알아보고, 계절의 변화와 관련된 교육에 시사점을 주는 데 있다. 이를 위해 문헌 연구를 기반으로 개념 시뮬레이션 과정 및 전략 분석틀을 개발하였으며, 과학교육 전문가 4인의 내용타당도를 확인 받았다. 연구의 결과는 다음과 같다. 첫째, 계절의 변화 원인 설명 과정에서 초등학생들은 주로 과학수업에서 모형 실험을 통해 학습한 지각적 경험을 이용하여 설명을 만들고 있었으며, 친숙한 대상을 이용하여 사고실험 사례를 고안하거나, 친숙한 지각적 경험을 유추하여 설명을 확고히 하는 것을 돕고 있었다. 둘째, 개념 시뮬레이션 사례의 실수는 초기표상의 진술, 심상 시뮬레이션의 실행 과정에서 나타났으며, 참여자들의 초기표상 진술이 불완전하거나, 심상 시뮬레이션 실행에서 부적절한 상황을 떠올린 경우였다. 셋째, 초등학생들의 개념 시뮬레이션 과정에서 남중고도의 개념과 관련된 정신모델을 확고히 하기 위해 제거, 대체의 시뮬레이션 전략을 사용하는 것을 확인하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권10호
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• pp.1455-1459
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• 2003

A $2{\times}3$ factorial design was used to study the impact of rearing systems, individual (I) vs. group (G) and different levels of milk/skim milk feeding (three schedules, F1, F2 and F3) on performance of crossbred (Bos indicus ${\times}$ Bos taurus) calves. Six calves (three from each sex) were taken in each group on the basis of their birth weight. All the calves were fed colostrum for three days and thereafter, were allotted to three different milk feeding schedules (F), i.e. milk fed upto 8 weeks of age (F1), milk upto 4 weeks followed by 50% (F2) and 100% (F3) replacement of milk with skim milk in the next 4 weeks. Calf starter and cereal green fodder were fed ad libitum to all the calves beginning from second week of age. A digestibility trial was conducted at 15th week of age to assess nutrient utilization during postweaning period. The digestibilty of dry matter (DM), organic matter, total carbohydrate, ether extract and crude protein (CP) were nonsignificant between the rearing systems and the feeding schedules. There was significantly higher digestibility of NDF and ADF in G than I and in F3 than F1 and F2. The concentration CP and total digestible nutrients of the diet ranged from 17.18 to 17.75% and 66.32 to 70.14%, respectively. The DM intake (kg/100 kg body weight) ranged from 1.74 to 2.14 kg during 0 to 8 weeks and 3.19 to 3.41 kg during 0 to 14 weeks of age. The effects during postweaning phase (9-14 weeks of age) showed increased performance in group housed calves compared to individually housed ones with a superior average daily gain (590 vs. 443 g) and dry matter intake (1.79 vs. 1.64 kg). Above all, replacement of milk with skim milk at 50% level after 4th week followed by complete removal after 6th week of age (F2) seemed to suit better in coping with immediate energy starvation due to sole feeding of skim milk (F3) and they performed the best under group housed system of rearing.

• ETRI Journal
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• 제38권4호
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• pp.675-684
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• 2016

This paper demonstrates the effect of fluoride-based plasma treatment on the performance of $Al_2O_3/AlGaN/GaN$ metal-insulator-semiconductor heterostructure field effect transistors (MISHFETs) with a T-shaped gate length of $0.20{\mu}m$. For the fabrication of the MISHFET, an $Al_2O_3$ layer as a gate dielectric was deposited using atomic layer deposition, which greatly decreases the gate leakage current, followed by the deposition of the silicon nitride layer. The silicon nitride layer on the gate foot region was then selectively removed through a reactive ion etching technique using $CF_4$ plasma. The etching process was continued for a longer period of time even after the complete removal of the silicon nitride layer to expose the $Al_2O_3$ gate dielectric layer to the plasma environment. The thickness of the $Al_2O_3$ gate dielectric layer was slowly reduced during the plasma exposure. Through this plasma treatment, the device exhibited a threshold voltage shift of 3.1 V in the positive direction, an increase of 50 mS/mm in trans conductance, a degraded off-state performance and a larger gate leakage current compared with that of the reference device without a plasma treatment.

• 대한전자공학회논문지SP
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• 제39권3호
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• pp.58-65
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• 2002

본 논문에서는 프레임간 압축된 영상의 블록화 현상을 감소시키기 위해 재구성하기 전 차분 영상을 처리하는 새로운 복원 알고리듬을 제안한다. 프레임내 압축 영상의 블록화 현상은 오직 8×8 DCT에 의해서 일어나는 반면에, 프레임간 압축된 영상에서는 8×8 DCT뿐만 아니라 움직임 보상을 위해 사용한 16×16의 매크로 블록에 의해서 발생된다. 이러한 이유로 본 논문에서는 차분 영상에 대한 새로운 열화모델을 제시하고, 블록 경계와 내부의 불연속에 대한 POCS를 이용한 복원 알고리듬을 제시한다. 제안된 알고리듬은 DCT계수의 일부를 이용해 블록 경계의 방향을 고려하는 공간 적응적 저대역 통과 필터를 포함하는 표준 정규화의 변환된 형태이다. 일반적인 비디오 압축 표준은 블록을 기준으로 하는 움직임 보상과 블록 이산여현 변환(BDCT)을 이용한 혼성(hybrid) 구조를 채택하고 있다. 이러한 이유에서 블록화 현상은 블록 경계와 블록 내부에서 일어난다. 두 종류의 블록화 현상을 좀 더 완벽히 제거하기 위해서 복원된 차분 영상은 블록 경계와 블록 내부에서의 방향성 불연속과 같은 제약조건을 만족시켜야만 한다. 그러한 제약조건은 차분 영상을 복구하기 위한 convex set을 정의하는데 이용한다.

• Journal of Periodontal and Implant Science
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• 제29권3호
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• pp.539-553
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• 1999

The purpose of this 6-months study was to compare the clinical and radiographic outcomes following guided tissue regeneration treating human mandibular Class II furcation defects with a bioabsorbable BioMesh barrier(test treatment) or a nonabsorbable ePTFE barrier(control treatment). Fourteen defects in 14 patients(mean age 44 years) were treated with BioMesh barriers and ten defects in 10 patients(mean age 48 years) with ePTFE barriers. After initial therapy, a GTR procedure was done. Following flap elevation, root planing, and removal of granulation tissue, each device was adjusted to cover the furcation defect. The flaps were repositioned and sutured to complete coverage of the barriers. A second surgical procedure was performed at control sites after 4 to 6 weeks to remove the nonresorbable barrier. Radiographic and clinical examinations(plaque index, gingival index, tooth mobility, gingival margin position, pocket depth, clinical attachment level) were carried out under standardized conditions immediately before and 6 months after surgery. Furthermore, digital subtraction radiography was carried out. All areas healed uneventfully. Surgical treatment resulted in clinically and statistically equivalent changes when comparisons were made between test and control treatments. Changes in plaque index were 0.7 for test and 0.4 for control treatments; changes in gingival index were 0.9 and 0.5. In both group gingival margin position and pocket depth reduction was 1.0mm and 3.0mm; clinical attachment level gain was 1.9mm. There were no changes in tooth mobility and the bone in radiographic evaluation. No significant(p${\leq }$0.05) difference between the two membranes could be detected with regard to plaque index, gingival index, gingival margin position, pocket depth, and clinical attachment level. In conclusion, a bioabsorbable BioMesh membrane is effective in human mandibular Class II furcation defects and a longer period study is needed to fully evaluate the outcomes.

• 한국지반환경공학회 논문집
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• 제17권11호
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• pp.35-43
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• 2016

이 연구는 복합발효미생물을 이용하여 유수지 악취 제거와 유수지 토양에 흡착된 오염물질의 정화효과를 확인하고, 현장 적용성 시험을 바탕으로 토양오염 정화시스템을 개발하기 위한 것이다. 토양 내에 침전된 유기오염물질을 분석하여 악취유발 원인과 토양오염 물질을 확인하였다. 개발된 복합발효미생물과의 혼합발효를 이용하여 악취와 오염물질을 분해하는 것이 가능함을 확인하였으며, 유수지 오염토의 물리 화학적 구성과 토양에 흡착된 오염물질을 확인하여 악취의 원인을 규명하였다. 또한, 복합발효미생물과 유수지토의 혼합실험을 통해 혼합방법에 따른 오염물질 제거효율을 분석하였다. 아울러, 복합미생물을 이용한 악취 제거 방법은 한 종류의 미생물을 이용하는 것보다 오염 제거에 효과적임을 확인하였다. 복합발효미생물을 이용한 방법은 자연정화처리 방법에 비해 악취농도가 2.5배 저감하는 것으로 측정되었으며, 토양으로부터 배출된 간극수의 수질이 개선된 것으로 나타났다. 또한, 복합발효미생물과 유수지 혼합토의 교반실험에서 토양입자 표면에 흡착된 구리와 납이 각각 65%와 66%로 저감되는 것을 확인하였으며, 유기물인 TPH 성분은 85%의 저감 효과가 있는 것을 확인하였다. 복합미생물을 이용한 유수지 오염토의 복원은 교반과 혼합비에 대한 기초자료 축적을 통해 악취와 토양오염을 효율적으로 저감시킬 수 있는 장기적인 정화시스템을 개발하고 적용할 필요가 있다.

• Journal of Periodontal and Implant Science
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• 제45권2호
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• pp.56-61
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• 2015

Purpose: The aim of this study was to evaluate the effectiveness of powered toothbrushes for plaque control in patients with peri-implant mucositis, in comparison with manual toothbrushes. Methods: This randomized, prospective, controlled, clinical parallel study compared the efficacy of manual and powered toothbrushes for plaque control in implant restorations. Patients with bleeding on probing, no residual pocket depth (as indicated by a pocket probing depth ${\geq}5mm$), and no radiological peri-implant bone loss were eligible for this study. Patients were requested to complete a questionnaire describing their oral hygiene habits. The duration and frequency of tooth brushing were recorded by subjects in order to assess their compliance. Clinical parameters, including the modified plaque index (mPI), the modified sulcus bleeding index (mSBI), and clinical photographs (buccal and lingual views) were recorded at baseline and at one-month and two-month follow-up visits. Results: Statistically significant differences between patients who used manual toothbrushes and those who used powered toothbrushes were found regarding the frequency of tooth brushing per day and the duration of brushing at one-month and two-month follow-up visits, while no statistically significant differences were found relating to other oral hygiene habits. A statistically significant difference in patient compliance for tooth brushing was found at one month, while no difference was found at two months. Statistically significant decreases in the mPI and the mSBI were observed in both groups from baseline to the one- and two-month follow-ups. The overall reduction of these parameters was not significantly different between the two groups, except for mPI reduction between baseline and one month of follow-up. Conclusions: Sonic-powered toothbrushes may be a useful device for plaque control in patients with peri-implant mucositis.

• Journal of Korean Neurosurgical Society
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• 제29권8호
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• pp.1001-1007
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• 2000

Objective : We analysed diverse clinical features of the cavernous angioma. Also, we report the experience in differ-ent methods of the management and their results. Method : Data from 80 patients who were confirmed pathologically or diagnosed radiologically between Jan. 1990 and Sept. 1998 at our hospital were analysed. Variable factors that were examined were : clinical features, effects of treatment, and complications. Results : There were 47 male and 33 female patients. The age at the first presentation was from 3 to 57(mean 34.1) years old. Clinical features were seizure in 28 cases(38%), bleeding in 24 cases(32%), neurologic deficits in 12 cases(16%), headache in 10 cases(14%), and six incidental cases. The locations of lesion were cerebral and cerebellar hemisphere in 45 cases(56.2%), brainstem, basal ganglia, and thalamus in 32 cases(40%), multiple in 3 cases (3.8%). Seizure was common at the third decade and occurred frequently with the cavernous angioma in temporal (43%) or frontal lobe(39%). Bleeding was frequent after the third decade with peak at the fourth decade and had high incidence in brainstem or thalamus. The gamma-knife radiosurgery was done in 47 cases. Rebleeding occurred in 3 cases, but it was within postradiosurgery 1 year. Symptomatic radiation change occurred in 2 cases of 8 radiation change on MRI. On follow-up MRI, no evidence of rebleeding was found in 30 cases. Also, The lesion size was decreased in 3 cases. Resection was performed in 23 cases ; total 20, subtotal 2, partial 1. Postoperative complication occurred in 6 cases(26.1%). After surgery, 7(63.6%) of 11 seizure patients had outcome of seizure-free. Subclinical rebleeding occurred in one of two subtotal resected cases. In 11 patients, conservative management was done. There was neither rebleeding nor symptom aggravation during follow-up period of mean 17.2 months. Conclusion : The solution for prevention of rebleeding is complete removal of the lesion located at noneloquent area or accessible region, especially for the patients who presented symptoms or intractable seizure. However, the Gamma knife radiosurgery is considered when the lesions are located at eloquent area or when severe postoperative morbidity is expected.

• Journal of Korean Neurosurgical Society
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• 제61권3호
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• pp.363-375
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• 2018

Intraoperative monitoring (IOM) utilizes electrophysiological techniques as a surrogate test and evaluation of nervous function while a patient is under general anesthesia. They are increasingly used for procedures, both surgical and endovascular, to avoid injury during an operation, examine neurological tissue to guide the surgery, or to test electrophysiological function to allow for more complete resection or corrections. The application of IOM during pediatric brain tumor resections encompasses a unique set of technical issues. First, obtaining stable and reliable responses in children of different ages requires detailed understanding of normal age-adjusted brain-spine development. Neurophysiology, anatomy, and anthropometry of children are different from those of adults. Second, monitoring of the brain may include risk to eloquent functions and cranial nerve functions that are difficult with the usual neurophysiological techniques. Third, interpretation of signal change requires unique sets of normative values specific for children of that age. Fourth, tumor resection involves multiple considerations including defining tumor type, size, location, pathophysiology that might require maximal removal of lesion or minimal intervention. IOM techniques can be divided into monitoring and mapping. Mapping involves identification of specific neural structures to avoid or minimize injury. Monitoring is continuous acquisition of neural signals to determine the integrity of the full longitudinal path of the neural system of interest. Motor evoked potentials and somatosensory evoked potentials are representative methodologies for monitoring. Free-running electromyography is also used to monitor irritation or damage to the motor nerves in the lower motor neuron level : cranial nerves, roots, and peripheral nerves. For the surgery of infratentorial tumors, in addition to free-running electromyography of the bulbar muscles, brainstem auditory evoked potentials or corticobulbar motor evoked potentials could be combined to prevent injury of the cranial nerves or nucleus. IOM for cerebral tumors can adopt direct cortical stimulation or direct subcortical stimulation to map the corticospinal pathways in the vicinity of lesion. IOM is a diagnostic as well as interventional tool for neurosurgery. To prove clinical evidence of it is not simple. Randomized controlled prospective studies may not be possible due to ethical reasons. However, prospective longitudinal studies confirming prognostic value of IOM are available. Furthermore, oncological outcome has also been shown to be superior in some brain tumors, with IOM. New methodologies of IOM are being developed and clinically applied. This review establishes a composite view of techniques used today, noting differences between adult and pediatric monitoring.

• 대한정형외과스포츠의학회지
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• 제9권1호
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• pp.28-34
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• 2010

목적: 본 연구는 이중 다발 전방십자인대 재건술 후의 단기 임상결과와 이차적 관절경 소견을 알아보았다. 대상 및 방법: 이중 다발 전방십자인대 재건술 후에 최소 24개월 이상 추시가 가능하였던 49 예(환자)를 대상으로 하였다. 임상적 결과로 Lysholm 슬관절 점수, Tegner 활동 점수, 도수 및 기계적 전방 안정성 검사를 시행하였다. 15 예에서 스테플 제거와 함께 이차적 관절경 수술을 시행하여, 재건된 전방십자인대의 파열 유무와 이식건의 주관적인 긴장 정도 및 활액막 형성 정도를 검사하였다. 결과: Lysholm 슬관절 및 Tegner 활동 점수는 각각 술전 67.4, 2.0에서 최종 추시에 96.1, 6.1로 호전되었다 (p<0.01). Lachman 및 pivot-shift 검사에서 39예, 36예가 정상범위로 호전되었다. 스트레스 방사선 검사의 양측 차이 정도는 10.8 mm 에서 3.3 mm로 의미있게 호전되었다 (p<0.01). 이차적 관절경 소견상 모든 환자에서 전내측 다발이 정상 및 정상에 가까운 소견이 관찰되었으나, 8예 (53.3%) 에서 후외측 다발의 부분 및 완전 파열이 관찰되었다. 결론: 이중 다발 전방십자인대 재건술이 임상적으로 슬관절의 회전 및 전, 후방 안정성을 복원하는 효과적인 수술법이라도, 이차적 관절경 수술을 시행한 증례의 몇 예에서 후 외측 다발의 파열이 관찰되었다.