• Korean Journal of Radiology
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• 제21권8호
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• pp.987-997
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• 2020

Objective: Measurement of the liver and spleen volumes has clinical implications. Although computed tomography (CT) volumetry is considered to be the most reliable noninvasive method for liver and spleen volume measurement, it has limited application in clinical practice due to its time-consuming segmentation process. We aimed to develop and validate a deep learning algorithm (DLA) for fully automated liver and spleen segmentation using portal venous phase CT images in various liver conditions. Materials and Methods: A DLA for liver and spleen segmentation was trained using a development dataset of portal venous CT images from 813 patients. Performance of the DLA was evaluated in two separate test datasets: dataset-1 which included 150 CT examinations in patients with various liver conditions (i.e., healthy liver, fatty liver, chronic liver disease, cirrhosis, and post-hepatectomy) and dataset-2 which included 50 pairs of CT examinations performed at ours and other institutions. The performance of the DLA was evaluated using the dice similarity score (DSS) for segmentation and Bland-Altman 95% limits of agreement (LOA) for measurement of the volumetric indices, which was compared with that of ground truth manual segmentation. Results: In test dataset-1, the DLA achieved a mean DSS of 0.973 and 0.974 for liver and spleen segmentation, respectively, with no significant difference in DSS across different liver conditions (p = 0.60 and 0.26 for the liver and spleen, respectively). For the measurement of volumetric indices, the Bland-Altman 95% LOA was -0.17 ± 3.07% for liver volume and -0.56 ± 3.78% for spleen volume. In test dataset-2, DLA performance using CT images obtained at outside institutions and our institution was comparable for liver (DSS, 0.982 vs. 0.983; p = 0.28) and spleen (DSS, 0.969 vs. 0.968; p = 0.41) segmentation. Conclusion: The DLA enabled highly accurate segmentation and volume measurement of the liver and spleen using portal venous phase CT images of patients with various liver conditions.

• Korean Journal of Radiology
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• 제1권1호
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• pp.25-32
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• 2000

Objective: The purpose of our study was to determine the ability of H-1 MR spectroscopy (MRS) to lateralize the lesion in patients with hippocampal sclerosis. Materials and Methods: Twenty healthy volunteers and 25 patients with intractable temporal lobe epilepsy whose MR imaging diagnosis was unilateral hippocampal sclerosis were included. This diagnosis was based on the presence of unilateral atrophy and/or high T2 signal intensity of the hippocampus. Single-voxel H-1 MRS was carried out on a 1.5-T unit using PRESS sequence (TE, 136 msec). Spectra were obtained from hippocampal areas bilaterally with volumes of interest (VOIs) of 6.0 cm³ and 2.25 cm³ in healthy volunteers, and of either 6.0 cm³ (n = 14) or 2.25 cm³ (n = 11) in patients. Metabolite ratios of NAA/Cho and NAA/Cr were calculated from relative peak height measurements. The capability of MRS to lateralize the lesion and to detect bilateral abnormalities was compared with MR imaging diagnosis as a standard of reference. Results: In healthy volunteers, NAA/Cho and NAA/Cr ratios were greater than 0.8 and 1.0, respectively. In patients, the mean values of these ratios were significantly lower on the lesion side than on the contralateral side, and lower than those of healthy volunteers (p < .05). The overall correct lateralization rate of MRS was 72% (18/25); this rate was lower with a VOI of 6.0 cm³ than of 2.25 cm³ (64% versus 82%, p < .05). Bilateral abnormalities on MRS were found in 24% (6/25) of cases. Conclusion: Although its rate of correct lateralization is low, single-voxel H-1 MRS is a useful and promising diagnostic tool in the evaluation of hippocampal sclerosis, particularly for the detection of bilateral abnormalities. To improve the diagnostic accuracy of H-1 MRS, further investigation, including the use of a smaller VOI and measurement of the absolute amount of metabolites, are needed.

• Korean Journal of Radiology
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• 제21권6호
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• pp.670-683
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• 2020

Objective: The presence of coagulative necrosis (CN) in clear cell renal cell carcinoma (ccRCC) indicates a poor prognosis, while the absence of CN indicates a good prognosis. The purpose of this study was to build and validate a radiomics signature based on preoperative CT imaging data to estimate CN status in ccRCC. Materials and Methods: Altogether, 105 patients with pathologically confirmed ccRCC were retrospectively enrolled in this study and then divided into training (n = 72) and validation (n = 33) sets. Thereafter, 385 radiomics features were extracted from the three-dimensional volumes of interest of each tumor, and 10 traditional features were assessed by two experienced radiologists using triple-phase CT-enhanced images. A multivariate logistic regression algorithm was used to build the radiomics score and traditional predictors in the training set, and their performance was assessed and then tested in the validation set. The radiomics signature to distinguish CN status was then developed by incorporating the radiomics score and the selected traditional predictors. The receiver operating characteristic (ROC) curve was plotted to evaluate the predictive performance. Results: The area under the ROC curve (AUC) of the radiomics score, which consisted of 7 radiomics features, was 0.855 in the training set and 0.885 in the validation set. The AUC of the traditional predictor, which consisted of 2 traditional features, was 0.843 in the training set and 0.858 in the validation set. The radiomics signature showed the best performance with an AUC of 0.942 in the training set, which was then confirmed with an AUC of 0.969 in the validation set. Conclusion: The CT-based radiomics signature that incorporated radiomics and traditional features has the potential to be used as a non-invasive tool for preoperative prediction of CN in ccRCC.

• 인삼문화
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• 제6권
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• pp.116-134
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• 2024

본 연구는 인삼 시장에 대한 분석을 통해 고려인삼 수출의 문제점을 파악하고자 하였다. 따라서 본 연구는 동북아시아의 주요 인삼 생산국인 한국과 중국의 인삼 경작면적, 수확 면적, 생산량 등의 인삼 생산 현황에 대해 파악하였고 한국의 경우 인삼의 평균 가격, 경영비용, 생산비용 등을 별도로 정리함으로써 생산 측면의 고려인삼의 생산 경쟁력을 보여주고자 하였다. 이어 주요 인삼수출국으로서의 한국, 중국, 홍콩의 수출량, 수출액, 수출단가와 같은 수출 동향과 주요 수출 품목 및 관세율 등의 수출 데이터를 정리하여 고려인삼의 수출 경쟁력을 보여주고자 하였다. 이에 덧붙여 중국, 홍콩, 대만의 인삼 소비 현황을 다양한 사례와 사건을 통해 보여줌으로써 수출국 현지의 소비 형태를 파악하고자 하였다. 생산, 수출, 소비 등에 대한 정보를 미루어봤을 때, 본 연구는 고려인삼의 수출 과정의 장애 요소를 수출시장의 경기침체, 취약한 고려인삼의 가격 경쟁력, 중국 삼과 서양 삼 등 경쟁제품의 시장점유율 증가, 홍보와 판촉의 부족, 다양한 인삼 제품의 개발과 수출의 부족 등으로 도출했다. 동시에 이를 극복하기 위한 방법으로 수출 다각화, 효과적인 생산 시스템 구축, 품질 및 브랜드 강화, 홍보와 마케팅 강화, 다양한 제품 개발 등의 전략을 제안한다.

• 한국문헌정보학회지
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• 제58권2호
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• pp.57-80
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• 2024

아이즈너는 교육과정 개발에 있어서 행동목표 외에 문제해결목표, 표현목표의 중요성과 언어적, 시각적, 청각 모드 등 멀티 모달에 의한 의사소통을 강조하였다. 본 연구는 정보활용교육을 위해서 개발된 교과서인 '도서관과 정보생활'을 교육목표 유형(행동목표, 문제해결목표, 표현목표)과 멀티 모달(언어적, 시각적, 청각적, 공간적, 행동적)을 기준으로 분석하여, 정보활용교육을 위한 교육목표 설정과 교과서 개발을 위한 시사점을 도출하고자 한다. '도서관과 정보생활' 교과서는 초등학교 저학년용, 초등학교 고학년용, 중학생용, 고등학생용의 4책으로 구성되어 있다. 교과서로부터 교육목표를 추출하여, 사서교사 3인에게 교육목표 분석을 의뢰하였다. 본 연구의 주요 결과와 시사점은 다음과 같다. 첫째, 교육목표 유형별로 볼 때, 행동목표의 비중이 지나치게 높게 나타났으며, 문제해결목표와 표현목표의 비중을 강화할 필요가 있다. 둘째, 문제해결목표는 행동목표와 중복되는 경향이 있으며, 조건과 해결책의 요건을 갖춘 진정한 의미의 문제해결목표를 개발할 필요가 있다. 셋째, 특정 대-단원에 집중되어 있는 표현목표는 다른 대-단원에서도 고르게 배치할 필요가 있다. 넷째, 멀티 모달의 경우 언어적 모드의 비중을 줄이고, 시각적, 청각적, 공간적, 행동적 모드의 비중을 높여야 하며, 각 모드의 특성이 명확한 교육목표를 설정할 필요가 있다.

• Journal of Chest Surgery
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• 제57권4호
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• pp.371-379
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• 2024

Background: Sutureless valves are widely used in aortic valve replacement surgery, with Perceval valves and Intuity valves being particularly prominent. However, concerns have been raised about postoperative thrombocytopenia with Perceval valves (Corcym, UK). We conducted a comparative analysis with the Intuity valve (Edwards Lifesciences, USA), and assessed how thrombocytopenia affected patient and transfusion outcomes. Methods: Among 595 patients who underwent aortic valve replacement from June 2016 to March 2023, sutureless valves were used in 53 (Perceval: n=23; Intuity: n=30). Platelet counts were monitored during hospitalization and outpatient visits. Daily platelet count changes were compared between groups, and the results from patients who underwent procedures using Carpentier Edwards Perimount Magna valves were used as a reference group. Results: Compared to the Intuity group, the Perceval group showed a significantly higher amount of platelet transfusion (5.48±1.64 packs vs. 0.60±0.44 packs, p=0.008). During the postoperative period, severe thrombocytopenia (<50,000/μL) was significantly more prevalent in the Perceval group (56.5%, n=13) than in the Intuity group (6.7%, n=2). After initial postoperative depletion, daily platelet counts increased, with significant differences observed in the extent of improvement between the Perceval and Intuity groups (p<0.001). However, there was no significant difference in early mortality or the incidence of neurological complications between the 2 groups. Conclusion: The severity of postoperative thrombocytopenia differed significantly between the Perceval and Intuity valves. The Perceval group showed a significantly higher prevalence of severe thrombocytopenia and higher platelet transfusion volumes. However, thrombocytopenia gradually recovered during the postoperative period in both groups, and the early outcomes were similar in both groups.

• 토지주택연구
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• 제15권3호
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• pp.113-127
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• 2024

부동산 시장에서 언론매체는 투자정보의 주요 출처로, 투자심리 변화에 큰 영향을 미친다. 본 연구는 2012년 1월부터 2022년 12월까지 전국 주택 및 토지 거래량 지표를 기준으로 부동산경기를 3개의 순환기로 나누어 분석하였다. 빅카인즈에서 제공하는 54개의 언론매체로부터 '부동산 투자심리' 검색어로 수집된 기사 중 제목 3,387건, 본문 8,544건을 대상으로 주요 단어를 빈도 분석하고, LDA 기법을 적용하여 토픽 모델링 분석을 수행하였다. 분석 결과, 제1순환기(2012-2015)에는 아파트 분양시장 관련 기사가 주를 이루며, 실수요와 투자 수요의 기대에 대한 보도가 많았다. 정책 변화에 대한 기대가 투자심리에 영향을 미쳤으나, 실제 투자로 이어지지 않는 경우도 많았다. 제2순환기(2016-2018)에는 금리 인상 및 집값 상승에 대한 기사가 많았으며, 수도권 및 강남지역의 부동산 가격 상승 기대가 주요 투자심리를 형성했다. 금리 변화와 연계된 부동산 거래량 변화가 많이 보도되었다. 제3순환기(2019-2022)에는 COVID-19 위기와 부동산 시장의 불안과 양극화, 정부 정책의 실패로 인한 투자심리의 왜곡과 쏠림 현상을 비판하는 내용이 많았다. 부동산 시장의 혼란과 가격 하락, 실질적인 거래 감소가 언론에 많이 보도되었으며, 이는 투자심리의 위축으로 이어졌다. 요약하면, 각 순환기마다 부동산 정책, 금리, 경제적 사건들이 투자심리에 중요한 영향을 미쳤으며, 언론보도는 이러한 심리 변화를 반영하고 있는 것으로 나타났다.

• International Journal of Computer Science & Network Security
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• 제24권7호
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• pp.128-142
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• 2024

Creation and implementation of export-oriented strategy is an urgent issue of economic development of any country. In an export-oriented model of economic development, exports should be a means of promoting economic growth and a tool to strengthen existing and potential competitive advantages. Agricultural production is the key factor in exports and the source of foreign exchange earnings in many countries. However, the export potential of agricultural producers may be inefficiently fulfilled due to the heterogeneity of countries in terms of economic development, trade relations and border policy. The aim of the research is to study the nature, main trends and problematic aspects of fulfilling the export potential of agricultural production in the context of aggravating food crisis. The study involved general scientific methods (induction and deduction, description, analysis, synthesis, generalization) and special (statistical method, economic analysis, descriptive statistics and interstate comparisons, graphical method). The need to ensure food security by countries around the world urges the importance of the agricultural sector as a catalyst for economic development, sources of foreign exchange earnings, investment direction, etc. The study of agricultural specialization led to the conclusion that wheat and sugar are goods with the highest export potential. It is substantiated that the countries of South America, OECD, North America and Europe have the highest level of realization of export potential of agricultural production, and African countries are import-dependent. In addition, the low export orientation of Africa and Asia due to the peculiarities of their natural and climatic conditions is established based on the assessment of export-import operations in the regional context. The internal and external export potential of each of the regions is analysed. Economic and mathematical simulation of assessing the impact of the most important factors on the wheat exports volumes was applied, which allowed predicting wheat exports volume and making sound management decisions regarding the realization of the export potential of agricultural companies. The inverse correlation between the exports volume and wheat consumption per capita, and the direct correlation between the effective size and area of land used for wheat cultivation was established through the correlation and regression analysis.

• 한국간담췌외과학회지
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• 제26권3호
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• pp.257-262
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• 2022

Backgrounds/Aims: Middle hepatic vein (MHV) is usually preserved as a part of the right or left hepatectomy in order preserve the venous outflow of remnant liver. The aim of this study was to evaluate if resection of MHV could influence post-resection outcomes of standard right or left hepatectomy. Methods: Patients who underwent standard right or left hepatectomy between January 2015 and December 2019 were included. Anatomical remnant liver volumes were measured retrospectively using the Hermes workstation (Hermes Medical Solutions AB, Stockholm, Sweden). Uni- and multi-variate analyses were performed to assess the difference in outcomes of those with preservation of MHV and those without preservation. Results: A total of 144 patients were included. Right hepatectomy was performed for 114 (79.2%) and left hepatectomy was performed for 30 (20.8%) patients. MHV was resected for 13 (9.0%) in addition to the standard right or left hepatectomy. Median remnant liver volume was significantly higher in the MHV resected group (p < 0.01). There was no significant difference in serum level of bilirubin, international normalized ratio, alanine aminotransferase, creatinine on postoperative day 1, 3, 5, or 10, ≥ grade IIIa complications (p = 0.44), or 90-day mortality (p = 0.41). On multivariable analysis, resection of the MHV did not influence the incidence of post hepatectomy liver failure (p = 0.52). Conclusions: Resection of the MHV at standard right or left hepatectomy did not have a negative impact on postoperative outcomes of patients with adequate remnant liver volume.

• 대한토목학회논문집
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• 제44권3호
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• pp.349-360
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• 2024

본 연구에서는 레벨4 이상의 완전자율주행자동차(autonomous vehicle)의 혼입률과 교통량의 변화에 따른 도로 네트워크의 성능 분석을 목적으로 하였다. 먼저, 자율주행자동차의 차량제어변수 관련 선행연구 검토와 전문가 설문 조사를 통해 자율주행 시장점유율 50 %로 예측되는 시점인 2040년의 장래 교통 수요를 예측해 이를 시뮬레이션 분석에 반영하였다. 또한, 승용차, 화물차, 버스의 자율주행 혼입률 및 교통량을 0~100 %까지 단계별 25 %씩 증가시켜가면서 연속류와 단속류의 교통흐름의 변화를 분석하였다. 분석 결과 교통량이 많아짐에 따라 통행시간이 증가함을 확인하였으며, 자율주행자동차 점유율이 증가 즉, 기술의 발전에 따른 통행시간 감소 패턴도 확인할 수 있다. 나아가, 자율주행자동차 점유율이 증가함에 따라 통행속도는 증가하는 추세를 보임도 확인할 수 있었다. 본 연구에서는 자율주행자동차 혼입률을 증가시키면서 교통량과 속도의 조합에 따른 한계대체율 산정을 통해 한계대체율 체감(law of diminishing MRS)의 법칙이 성립함을 확인하였다. 나아가 무차별 곡선의 볼록성도 단속류와 연속류 환경에서 모두 성립함을 확인하였다.