• 한국수학교육학회지시리즈E:수학교육논문집
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• 제22권2호
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• pp.229-252
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• 2008

The purpose of this research was to make fair assessment methods which took into account characteristics of mathematically underachievers. The researchers devised an descriptive tests and interviews and applied them to the mathematics underachievers who could not reveal their achievements in the traditional assessment and then analyzed their cognitive and affective characteristics in the alternative assessments. After selecting three students by the normal assessment made of simple subjective and multiple choice questions, the cognitive and affective characteristics found in the general assessment were reflected to the descriptive tests and interviews. The descriptive tests and interviews are comprised of descriptive narrations and informal interview questions. After the assessment, the teacher and students gave feedbacks one another. All the assessment activities were recorded by a camcorder to analyze cognitive and affective characteristics of the children. Throughout the research, the following conclusions were made. The mathematics underachievers showed the characteristics which didn't appeared in the normal assessment. They showed normal abilities of problem solving and communication In the cognitive area. Also they brought in positive result in most parts in the affective area. However, the student B displayed considerable ability of mathematical thinking that is over the average level of mathematical underachievers. This implies that we can definite the mathematical underachievers differently when we use the detailed and relief assessment method instead of the traditional assessment. On the other hand, one student tended to depend on the teacher and another student overheard what the others talk during the study. This defect should be complemented by the further studies about assessment method for the mathematical underachievers. Also appropriate assessment methods should be made for applying to the various mathematical underachievers. Many studies have been concentrated on the learning for mathematical underachievers but there is little concern about the assessment for the mathematical underachievers. However it is the fundamental way to reduce the number of mathematics underachievers that we construct consistent learning methods and assessments for the mathematical underachievers.

• Tuberculosis and Respiratory Diseases
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• 제69권2호
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• pp.124-128
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• 2010

Septic pulmonary embolism is the process in which an infected thrombus becomes detached from its site of origin and lodges in a pulmonary artery, and is usually associated with infective endocarditis, especially right-sided, or infection-associated with indwelling catheters, peripheral septic thrombophlebitis, and periodontal diseases, etc. Here, we report a case of septic pulmonary embolism associated with tricuspid valve infective endocarditis. A 23-year-old female was admitted to our hospital, due to fever, sore throat, and myalgia. In her past medical history, she had undergone a surgical operation for closure of a ventricular septal defect, but was informed that the operation resulted in an incomplete closure. The initial chest radiograph demonstrated multiple rounded, parenchymal nodules in various sizes; several nodules had central lucency suggesting cavitations. Echocardiography demonstrated a large vegetation attached to the septal tricuspid valve leaflet, extending from right ventricular inflow tract to outflow tract. Computed tomography of thorax revealed bilateral peripheral nodules and wedge-shaped consolidation at various sizes, mostly accompanied by cavitations.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.179-184
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• 2006

Rapid and high-precision positioning with a Global Navigation Satellite System (GNSS) is feasible only when very precise carrier-phase observations can be used. There are two kinds of mathematical models for ambiguity resolution. The first one is based on both pseudorange and carrier phase measurements, and the observation equations are of full rank. The second one is only based on carrier phase measurement, which is a rank-defect model. Though the former is more commonly used, the latter has its own advantage, that is, ambiguity resolution will be freed from the effects of pseudorange multipath. Galileo will be operational. One of the important differences between Galileo and current GPS is that Galileo will provide signals in four frequency bands. With more carrier-phase data available, frequency combinations with long equivalent wavelength can be formed, so Galileo will provide more opportunities for fast and reliable ambiguity resolution than current GPS. This paper tries to investigate phase only fast ambiguity resolution performance with four Galileo frequencies for short baseline. Cascading Ambiguity Resolution (CAR) method with selected optimal frequency combinations and LAMBDA method are used and compared. To validate the resolution, two tests are used and compared. The first one is a ratio test. The second one is lower bound success-rate test. The simulation test results show that, with LAMBDA method, whether with ratio test or lower bound success rate validation criteria, ambiguity can be fixed in several seconds, 8 seconds at most even when 1 sigma of carrier phase noise is 12 mm. While with CAR method, at least about half minute is required even when 1 sigma of carrier phase noise is 3 mm. It shows that LAMBDA method performs obviously better than CAR method.

• 한국통신학회논문지
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• 제34권2A호
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• pp.170-176
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• 2009

다중사용자 다중안테나 시스템은 단일사용자 다중안테나 시스템보다 더 좋은 성능을 가진다는 것이 알려져 있다. 그러나 다중사용자 다중안테나 시스템은 선택된 사용자들 간의 신호 간섭이 발생하기 때문에 그것을 제거해야 된다. 간섭 신호를 제거하는 기법 중에 가장 널리 쓰이는 방법으로서 zero-forcing beamforming (ZFBF) 방법이 있다. 하지만 이 방법은 상당히 정확한 채널 정보를 송신단이 알아야 되기 때문에 실제 시스템에서 사용되기 위해서는 많은 양의 피드백 비트수가 필요하게 된다. ZFBF의 단점을 보완하기 위해 Random Beamforming (RBF) 시스템이 제안되었다[1]. RBF는 미리 정해진 코드북에 가장 최적의 성능을 보이는 사용자들에게 데이터를 보내는 방법으로서, 각 수신단은 코드북 내의 최적의 성능을 가지는 코드워드의 인텍스와 CQI 정보를 피드백 한다. 그러나 [l]에서는 송신단이 각 수신단의 CQI 정보를 완벽히 안다고 가정을 하였는데 실제 시스템에서는 CQI 정보도 양자화 되어야 한다. 따라서 이번 논문에서는 CQI 정보를 효율적으로 양자화하는 방법을 제안한다.

• Journal of Genetic Medicine
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• 제11권2호
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• pp.86-90
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• 2014

Smith-Lemli-Opitz syndrome (SLOS) is a rare autosomal recessive disorder caused by 7-dehydrocholesterol reductase deficiency. The characteristic clinical features are syndactyly of the second and third toes, facial dysmorphism, multiple malformations, and intellectual disability. Few cases of SLOS have been reported in Korea. We observed a male patient with SLOS who presented with typical facial features, undescended testes, microcephaly, bilateral syndactyly of the second and third toes, and cardiac defects, including patent ductus arteriosus and atrial septal defect. Mutation analysis of the DHCR7 gene identified compound heterozygous mutations of c.907G>A (p.Gly303Arg) and c.1055G>A (p.Arg352Gln). In a review of the literature, c.1054C>T (p.Arg352Trp) was the most common mutation reported in Far East Asian countries. This report describes the clinical features, biochemical data, molecular characteristics, and clinical outcome of a Korean patient with SLOS.

• 대한치과교정학회지
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• 제51권5호
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• pp.304-312
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• 2021

Objective: This study aimed to compare the amount of tooth movement after multiple horizontal (MH) and single vertical (SV) micro-osteoperforations (MOPs), and evaluate the histological changes after orthodontic force application in rabbits. Methods: The mandibles of 24 white rabbits were subjected to two experimental interventions: MH and SV MOPs. Defect volume of the MOPs between the two groups was kept similar. A force of 100 cN was applied via a coil spring between the incisor teeth and the first premolars. The amount of tooth movement was measured. Differences in the amount of tooth movement and bone variables at three time points and between the two groups were evaluated using repeated-measures analysis of variance. Results: The first premolar showed a mesial movement of 1.47 mm in the MH group and 1.84 mm in the SV group, which was significantly different at Week 3 (p < 0.05). No significant difference was observed in bone volume and bone fraction between the groups. Tartrate-resistant acidic phosphatase-positive cell count was also significantly greater at Week 3 than at Week 1 in both the SV and MH groups. Conclusions: The amount of tooth movement showed significant differences between Weeks 1 and 3 in the SV and MH MOP groups, but showed no differences between the two groups. Therefore, SV MOP could be considered an effective tool for enhancing tooth movement, especially for molar distalization, uprighting, and protraction to an edentulous area.

• 전기전자학회논문지
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• 제26권2호
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• pp.219-225
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• 2022

우리나라의 섬유산업 중 염색가공 분야는 에너지 다소비 업종으로, 노동 집약적 특성에 따라 원단위 생산성이 낮고, 대부분 중소·영세기업 특징이 있다. 염색 원단의 불량률이 높아지면 재염색으로 인한 생산단가 상승과 초과 에너지 투입으로 비용이 증가하기 때문에, 불량률을 최소를 통한 생산량 향상이 초점이었다. 또한 고온고압의 환경에서 이루어지는 염색공정은 사고 위험으로 염색기 원단 투입구를 실시간으로 개방할 수 없기 때문에 실시간으로 원단의 염색상태 확인이 어려웠다. 최근에는 염액을 실시간으로 모니터링하는 연구가 활발히 진행중이다. 본 논문에서는 탁도, pH, 전도도 센서를 이용하여 염액의 흡진율을 계측할 수 있는 복합센서 흡진율 모델 및 구성시스템을 제안하였으며, 실험방법소개와 실험결과 분석을 실시하였다.

• 대한치과보철학회지
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• 제60권4호
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• pp.382-394
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• 2022

심한 치주염을 가진 환자의 치료는 환자의 개개 치아의 정확한 진단과 전략적인 치료 계획을 통해 단계적으로 진행되어야 한다. 임플란트 지지 고정성 보철 수복은 국소의치에 비해 환자의 만족도가 높고, 안정적인 수직 고경을 유지할 수 있는 장점이 있지만, 경조직이 부족한 다수 치아 결손 부위에서는 심미적인 측면의 실패와 치료 기간이 길어진다는 점의 단점이 있을 수 있다. 또한 통상의 고정성 보철물을 제작하고 장착하는 데에는 일정 기간이 소요되는데, 이 기간 동안 임시 보철물은 치아의 기계적, 생물학적, 심미적 요구 조건을 만족시켜야 한다. 이번 증례 보고에서는 상악과 하악의 부분 무치악 환자에서 단계적인 접근을 통한 임플란트 고정성 보철물을 수복한 증례를 보고하고자 한다.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1267-1267
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• 2001

The existing fruit sorter has the method of tilting tray and extracting fruits by the action of solenoid or springs. In peaches, the most sort processing is supported by man because the sorter make fatal damage to peaches. In order to sustain commodity and quality of peach non-destructive, non-contact and real time based sorter was needed. This study was performed to develop peach sorter using near-infrared spectroscopy in real time and nondestructively. The prototype was developed to decrease internal and external damage of peach caused by the sorter, which had a way of extracting tray with it. To decrease positioning error of measuring sugar contents in peaches, fiber optic with two direction diverged was developed and attached to the prototype. The program for sorting and operating the prototype was developed using visual basic 6.0 language to measure several quality index such as chlorophyll, some defect, sugar contents. The all sorting result was saved to return farmers for being index of good quality production. Using the prototype, program and MLR(multiple linear regression) model, it was possible to estimate sugar content of peaches with the determination coefficient of 0.71 and SEC of 0.42bx using 16 wavelengths. The developed MLR model had determination coefficient of 0.69, and SEP of 0.49bx, it was better result than single point measurement of 1999's. The peach sweetness grading system based on NIR reflectance method, which consists of photodiode-array sensor, quartz-halogen lamp and fiber optic diverged two bundles for transmitting the light and detecting the reflected light, was developed and evaluated. It was possible to predict the soluble solid contents of peaches in real time and nondestructively using the system which had the accuracy of 91 percentage and the capacity of 7,200 peaches per an hour for grading 2 classes by sugar contents. Draining is one of important factors for production peaches having good qualities. The reason why one farm's product belows others could be estimated for bad draining, over-much nitrogen fertilizer, soil characteristics, etc. After this, the report saved by the peach grading system will have to be good materials to farmers for production high quality peaches. They could share the result or compare with others and diagnose their cultural practice.

• Computers and Concrete
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• 제31권4호
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• pp.293-306
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• 2023

This study proposes and demonstrates a smart monitoring system that uses transmission lines embedded in a reinforced concrete structure to detect the presence of defects through changes in the electromagnetic waves generated and measured by a time-domain reflectometer. Laboratory experiments were first conducted to identify the presence of voids in steel-concrete composite columns. The results indicated that voids in the concrete caused a positive signal reflection, and the amplitude of this signal decreased as the water content of the soil in the void increased. Multiple voids resulted in a decrease in the amplitude of the signal reflected at each void, effectively identifying their presence despite amplitude reduction. Furthermore, the electromagnetic wave velocity increased when voids were present, decreased as the water content of the soil in the voids increased, and increased with the water-cement ratio and curing time. Field experiments were then conducted using bored piles with on-center (sound) and off-center (defective) steel-reinforcement cage alignments. The results indicated that the signal amplitude in the defective pile section, where the off-center cage was poorly covered with concrete, was greater than that in the pile sections where the cage was completely covered with concrete. The crosshole sonic logging results for the same defective bored pile failed to identify an off-center cage alignment defect. Therefore, this study demonstrates that electromagnetic waves can be a useful tool for monitoring the health and integrity of reinforced concrete structures.