• 한국수학교육학회지시리즈A:수학교육
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• 제55권4호
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• pp.397-416
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• 2016

This study analyzed the quality of mathematics classes with observations using the instrument, MQI(Mathematical Quality of Instruction). Class recordings and interviews were conducted on 2 pre-service teachers and 4 in-service teachers. This study recorded and analyzed 3 or 4 classes for each mathematics teacher by using revised MQI. There were a total of 8 raters: 2 or 3 raters analyzed each class. MQI has four dimensions: Richness of the Mathematics, Working with Students and Mathematic, Errors and Imprecision, Student Participation in Meaning-Making and Reasoning. In the dimension of 'Richness of Mathematics', all teachers had good scores of 'explanations of teacher' but had lower scores of 'linking and connections', 'multiple procedures or solution methods' and 'developing mathematical generalizations.' In the dimension of 'Working with Students and Mathematics', two in-service teachers who have worked and having more experience had higher scores than others. In the dimension of 'Errors and Imprecision', all teachers had high scores. In the dimension of 'Student Participation in Meaning-Making and Reasoning', two pre-service teachers had contrast and also two in-service teachers who hadn't worked not long had contrast. Implications were deducted from finding to improving quality of mathematics classes.

• 대한기계학회논문집B
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• 제28권12호
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• pp.1567-1572
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• 2004

Although accurate measurement of velocity profiles, multiple velocity vectors, and shear stress in arteries is important, there is still no easy method to obtain such information in vivo. This study shows the utility of combining ultrasound contrast imaging with particle image velocimetry (PIV) for non-invasive measurement of velocity vectors. The steady flow analytical solution and optical PIV measurements (for pulsatile flow) were used for comparison. When compared to the analytical solution, both echo PIV and optical PIV resolved the steady velocity profile well. Error in shear rate as measured by echo PIV (8%) was comparable to the error of optical PIV (6.5%). In pulsatile flow, echo PIV velocity profiles agreed well with optical PIV profiles. Echo PIV followed the general profile of pulsatile shear stress across the artery but underestimated wall shear at certain time points. These studies indicate that echo PIV is a promising technique for the non-invasive measurement of velocity profiles and shear stress.

• 한국전자통신학회논문지
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• 제13권4호
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• pp.859-864
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• 2018

본 논문에서는 여러 대의 저화질 카메라를 이용하여 두 영상을 합성 후 명암비 증가와 윤곽선 강조법을 이용한 영상 개선을 하였다. 두 대의 라즈베리 카메라를 이용하여 각각의 영상을 촬영한 후 매트랩을 이용하여 합성하였다. 합성 영상에 평균 연산(산술, 기하, 조화)을 적용한 후 교차영역을 추출하였다. 본 논문의 실험에서는 추출된 합성 영상에 윤곽선 강조 방법(언샤프마스크 필터, 하이부스트 필터)과 명암비 증가 방법(히스토그램 균등화, 히스토그램 스트레칭)을 적용하여 영상 개선 결과를 확인 및 비교하였다.

• Journal of Trauma and Injury
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• 제34권4호
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• pp.294-298
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• 2021

Extrahepatic biliary tract and gallbladder injuries following blunt abdominal trauma are uncommon. Traumatic cystic duct transection is even rarer, which has frequently caused missed diagnosis and delayed treatment. An 18-year-old female patient with no past medical history was transferred to the Trauma Center of Kyungpook National University Hospital after falling from a height of approximately 20 meters. She became hemodynamically stable after initial resuscitation, and initial contrast-enhanced abdominal computed tomography (CT) showed right kidney traumatic infarction and multiple intrahepatic contusions with minimal fluid collection but no extravasation of the contrast. She was admitted to the intensive care unit. On the second day of hospitalization, her abdomen became distended, with follow-up CT showing a large collection of intra-abdominal fluid. Laparoscopic exploration was then performed, which revealed devascularization of the gallbladder with complete transection of the cystic duct and artery. Laparoscopic cholecystectomy was performed, as well as primary closure of the cystic duct orifice on the common bile duct using a 4-0 Prolene suture. After surgery, no clinical evidence of biliary leakage or common bile duct stricture was observed.

• Korean Journal of Radiology
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• 제23권6호
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• pp.598-614
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• 2022

While ultrasound (US) is considered an important tool for hepatocellular carcinoma (HCC) surveillance, it has limited sensitivity for detecting early-stage HCC. Abbreviated MRI (AMRI) has recently gained popularity owing to better sensitivity in its detection of early-stage HCC than US, while also minimizing the time and cost in comparison to complete contrast-enhanced MRI, as AMRI includes only a few essential sequences tailored for detecting HCC. Currently, three AMRI protocols exist, namely gadoxetic acid-enhanced hepatobiliary-phase AMRI, dynamic contrast-enhanced AMRI, and non-enhanced AMRI. In this study, we discussed the rationale and technical details of AMRI techniques for achieving optimal surveillance performance. The strengths, weaknesses, and current issues of each AMRI protocol were also elucidated. Moreover, we scrutinized previously performed AMRI studies regarding clinical and technical factors. Reporting and recall strategies were discussed while considering the differences in AMRI protocols. A risk-stratified approach for the target population should be taken to maximize the benefits of AMRI and the cost-effectiveness should be considered. In the era of multiple HCC surveillance tools, patients need to be fully informed about their choices for better adherence to a surveillance program.

• 한국실내디자인학회논문집
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• 제22권2호
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• pp.194-202
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• 2013

Commercial spaces are very sensitive in terms of trend and uniqueness, and many elements expressing space coexist together with brilliant ideas aiming to attract consumer attention and even induce sudden desire of purchase. Coexistence in space is expressed in various ways and out of those ways, representation by material is especially apparent. The application of material does not individually influence the expression of space, but the characteristics of multiple materials applied contribute to the distinction of space through mutual communication. This study intends to analyze how conversion is centered to express the distinction of space through materials communicated in space. The detailed study results are as follows. First, the conversion expression method of material resulted as 'Substitution', 'Contrast', 'Assimilation', 'Creation'. These four was divided and analyzed into 'Time', 'Space', 'Genre'. As a result of this analysis, such significances were shown as 'Contrast' in 'Time', 'Substitution' in 'Space', and 'Assimilation' in 'Genre'. Second, the conflict due to heterogeneity by conversion of 'Contrast' in 'Time' through past and current materials appeared to induce interest amongst consumers. Third, within 'Space', 'Substitution' of natural/artificial materials was noticeably applied. This is evaluated as a constructive way of expressing natural forms into artificial forms further intending to provoke attention and stimulate emotion. Fourth, in conversion through 'Assimilation' in 'Genre', rather than using materials only from other areas, synchronizing it by combining architectural materials is an effective method. Such results are thought to be a distinctive design method that draws attention of customers by communicating disparate materials in commercial space. Thus, the study results are expected to be utilized as an elementary resource in designing commercial space with character and high satisfaction.

• Asian Pacific Journal of Cancer Prevention
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• 제16권3호
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• pp.1135-1138
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• 2015

Background: The objective of this study was to investigate the MSCT characteristics of PTL in order to enhance the awareness of this uncommon entity among both clinicians and radiologists. Materials and Methods: The clinicopathological data and MSCT images of 27 patients with PTL were retrospectively reviewed. The MSCT appearances were classified into three types: type 1, solitary nodule surrounded by normal thyroid tissue; type 2, multiple nodules in the thyroid, and type 3, enlarged thyroid glands with a reduced attenuation with or without peripheral thin hyperattenuating thyroid tissue. Results: The patients were enrolled in the study with a mean age of 68 years (range, 51-86years) and compression symptoms or enlarged cervical lymph nodes at diagnosis. Hashimoto's thyroiditis was in 20 patients. All patients had non-Hodgkin lymphoma of B-cell in origin, including 22 cases of diffuse large B-cell lymphoma (DLBCL) and 5 of low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT). For MSCT appearance, type 1 pattern was observed in 2 patients, type 2 in 8, and seventeen type 3 in 17. The lesions occurred in more than one lobe with a mean maximal transverse diameter of 6.9 cm and an ill-defined margin. Most tumors showed a homogeneous attenuation equal to that of surrounding muscles before contrast and obvious enhancement after contrast. Cervical lymph node involvement and invasion of the trahea and (or) esophagus were mainly observed in patients with DLBCL. Conclusions: PTL should be clinically considered in elder patients presenting with a history of Hashimoto's thyroiditis and cervical lymphadenopathy. The MSCT characteristics of PTL includes a mass diffusely affecting more than one thyroid lobe, isointense to muscle and obvious enhancement before and after contrast. DLBCL, the most common histological subtype of PTL, is associated with a higher invasive tendency.

• 감성과학
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• 제20권2호
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• pp.137-148
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• 2017

본 연구는 일련의 문자열들 중 하나의 표적을 탐지하는 데 자극 명암대비와 색상이 미치는 영향을 관찰하였다. 실험 1의 각 시행에서는 네 문자로 구성된 RSVP가 제시되고 각 RSVP 화면상의 문자들이 서로 다른 위치를 점유하였다. RSVP 배열 내에서는 한 위치에 회색 표적 문자가, 나머지 위치에 세 방해자극들이 제시된 표적화면을 제외하고 나머지 RSVP 화면에서 네 흰색 방해자극 문자들이 상응하는 위치에 제시되었다. 고가시성 조건에서는 회색 배경화면 보다 표적 회색이 현저히 어두웠던 반면 저가시성 조건에서는 그 밝기 차이가 상대적으로 분명치 않았다. 참가자들은 사전에 지정된 표적들 중 각 시행에서 어느 것이 출현했는지를 가능한 빠르고 정확하게 탐지하도록 요구받았으며 그 결과 관찰된 탐지 수행은 고가시성 조건에서 더 정확했으며 신속했다. 실험 2에서는 고가시성 조건의 회색 표적을 고선명도 유채색 표적으로 대체한 것을 제외하고 실험 1과 동일한 RSVP 화면 및 과제가 사용되었다. 그 결과 참가자들은 고가시성 조건의 표적을 더 정확히 탐지했으나 반응 속도에 있어서는 두 가시성 조건 간 차이가 없었다. 두 실험의 결과는 시각적 부담이 높은 상황일지라도 현저한 명암대비 및 색상이 부여될 경우 자극에 대한 지각이 촉진됨을 시사하며 자극 색상에 비해 명암대비가 지각적 촉진에 더 중요한 역할을 수행할 가능성을 제안한다.

• International Journal of Contents
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• 제14권3호
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• pp.7-16
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• 2018

The extent and depth of the event plan determines the scope of pedagogical experience in situations and consequently the quality of immersive learning based on our simulated world. In contrast to planning in conventional narrative-based systems mainly pursuing dramatic interests, planning in virtual world-based pedagogical systems strive to provide realistic experiences in immersed situations. Instead of story plot comprising predetermined situations, our inter-event planning method aims at simulating diverse situations that each involve multiple events coupled via their associated agents' conditions and meaningful associations between events occurring in a background world. The specific techniques to realize our planning method include, two-phase planning based on inter-event search and intra-event decomposition (down to the animated action level); autonomous and independent agents to behave proactively with their own belief and planning capability; full-blown background world to be used as the comprehensive stage for all events to occur in; coupling events via realistic association types including deontic associations as well as conventional causality; separation of agents from event roles; temporal scheduling; and parallel and concurrent event progression mechanism. Combining all these techniques, diverse exogenous events can be derived and seamlessly (i.e., semantically meaningfully) integrated with the original event to form a wide scope of situations providing chances of abundant pedagogical experiences. For effective implementation of plan execution, we devise an execution scheme based on multiple priority queues, particularly to realize concurrent progression of many simultaneous events to simulate its corresponding reality. Specific execution mechanisms include modeling an action in terms of its component motions, adjustability of priority for agent across different events, and concurrent and parallel execution method for multiple actions and its expansion for multiple events.

• 한국경영과학회지
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• 제33권4호
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• pp.13-30
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• 2008

We explore the determinants of long-term relationship between the buyer and the supplier to help suppliers develope a strategy to build long-term relationship with their buyers. Based upon an extensive literature review, we propose three droops of independent variables which may affect long-term relationship, including (a) environmental factors (product complexity, product importance, source dependence, price sensitivity), (b) relational factors(trust, commitment, satisfaction, intention of expansion), (c) operational performance(quality, delivery, cost capability, technical knowhow). The buyer's actual period of relationship with its main supplier is used as a dependent variable. Using hierarchical multiple regression analysis, we empirically test hypotheses, analysing a sample of 290 manufacturing firms in the U.S. The statistical results indicate that the buyer's source dependence, price sensitivity and the supplier's commitment play a significant role in establishing long-term relationship between the buyer and the supplier. However, the supplier's cost capability and technical knowhow in operational performance negatively affect long-term relationship in contrast with our hypotheses. Due to this controversial result, we divide the sample group Into dual sourcing and multiple sourcing environments and reconduct regression analysis in a post hoc manner. The findings show that the supplier's cost capability and technical knowhow are negatively associated with the length of relationship only in the multiple sourcing environment. The results may confirm that both parties' opportunistic behavior is more salient in the multiple sourcing environment than in the single sourcing environment.