• 한국전자파학회논문지
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• 제15권4호
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• pp.327-334
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• 2004

최근 빠르게 발전하고 있는 이동통신 서비스는 보다 만족스럽고 보다 우수한 성능의 무선 통신용 필터나 다이플렉서 혹은 트리플렉서와 같은 멀티플렉서를 요구하고 있다. 다이플렉서는 수신된 신호를 고주파와 저주파신호로 각각 분리하여 주는 소자로서 듀얼모드 단말기에 쓰이는 것으로 이미 잘 알려져 있다. 트리플렉서는 수신된 신호를 각각 세 개의 대역 즉 AMPS, GPS, US-PCS 등으로 구분하여 주는 소자로서 최근 서비스를 시작한 GPS 기능을 추가시키기 위한 triple-mode 소자라 할 수 있다. 하지만 GPS 대역(1.575 ㎓)과 US-PCS(1.85 ㎓∼l.91 ㎓) 대역이 서로 간섭을 일으킬 만큼 가깝기 때문에 각 출력단간의 Isolation 특성을 강화하는데 주력을 하였다. 본 연구에서 트리플렉서는 무라타 사의 인덕터와 캐패시터를 사용하였고, Agilent 사의 ADS를 이용하여 설계하였으며, 측정시 Agilent사의 VNA 8510C를 사용하여 측정하였다.

• 한국식생활문화학회지
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• 제32권1호
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• pp.1-9
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• 2017

The objective of this study was to explore the role of familiarity in cross-cultural product perception and perception changes according to food systems (hot sauce and spicy-chicken) in Korean and US consumers. Free choice profiling was conducted by Korean and US consumers on four spicy-chicken samples made using four hot sauce samples. Half of the hot sauce samples were selected to be more familiar to US consumers and vice versa to Korean consumers. A previous study that investigated cross-cultural perceptions of the same four hot sauce samples in US and Korean consumers was incorporated in this study. For distinct sample differences, US and Korean consumers perceived products similarly. However, for less obvious differences, flavor familiarity seemed to affect consumers' product perceptions. In addition, product perceptions changed more dramatically according to food systems for familiar samples in each country. The findings of this study show that consumers' product perception can be affected by flavor familiarities.

• Journal of Medicine and Life Science
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• 제20권2호
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• pp.73-82
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• 2023

Multiple studies have reported on unilateral axillary adenopathy following coronavirus disease 2019 (COVID-19) vaccination, which is currently recognized as a common finding. Here, we present a series of eight adult patients with reactive axillary lymphadenopathy following COVID-19 vaccination, in whom the follow-up ultrasonography (US) showed resolution of a previously noted unilateral axillary adenopathy. From March 2021 to March 2022, 2,599 consecutive women underwent breast US in Jeju National University Hospital. We identified 10 patients with unilateral axillary lymphadenopathy following COVID-19 vaccination detected on the breast US. The 10 patients were recommended for follow-up US. Two patients were lost to follow-up, whereas the remaining eight patients underwent follow-up US, in whom resolution of the unilateral axillary lymphadenopathy was noted. Radiologists should be aware of evolving guidelines for evaluating and managing axillary lymphadenopathy to avoid false positive biopsies. Recent studies on lymphadenopathy following COVID-19 vaccination show that a prolonged duration until resolution is often observed. Therefore, a follow-up US examination at least 12 weeks after vaccination may be reasonable. Furthermore, management guidelines should include a risk-stratified approach considering both vaccination timing and the patient's overall risk of metastatic disease.

• Strategy21
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• 통권45호
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• pp.5-32
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• 2019

본 논문을 통해, 필자는 국제정치학 패러다임을 통해 인도태평양전략이 갖는 의미를 살펴보고, 그 전략적 함의를 생각해보았다. 핵심 관찰사항으로, 첫째 미(美) 인도태평양전략은 미국의 국가정체성에 대한 선언이라는 것이다. 즉 미국이 인도-태평양 국가이고, 현존하는 국제질서를 만든 국가라는 것을 명확히 하면서, 앞으로도 그럴 것이라는 강력한 국가의 의지를 밝히고 있다. 특히, 필자는 인태전략이 자유롭고, 열린 인도-태평양을 지지하는 국가들 간의 집합적인 정체성, 즉 인도-태평양 커뮤니티의 형성을 추도하는 미국의 노력으로 볼 수 있다고 주장한다. 둘째, 인태전략은 국제안보의 위협 세력에 대한 억제전략이 라는 것을 설명한다. 셋째, 인태전략은 미국의 전략적 우위를 유지하면서 신흥강대국인 중국을 포용하는, 즉 강대국 간 충돌을 예방하기 위한 위험감소를 위한 노력이기도 하다, 특히, 인태전략은 기준, 규범, 국제제도와 같은 구성주의 요소들과 접근법을 활용함으로써, 정당성과 국제적 지지를 유지하는 동시대, 국제질서와 국익을 보장하는 잘 구성된 전략이다. 물론, 이에 대한 제한점과 도전 요인도 따를 것이다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제34권3호
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• pp.285-292
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• 2008

Purpose: The present study was performed to evaluate the effect of surface treatment of the cervical area of implant on bone regeneration in fresh extraction socket following implant installation. Materials and methods: The four minipigs, 18 months old and 30 kg weighted, were used. Four premolars of the left side of both the mandible and maxilla were extracted. ${\phi}$3.3 mm and 11.5 mm long US II plus implants (Osstem Implant co., Korea) with resorbable blasting media (RBM) treated surface and US II implants (Osstem Implant co., Korea) with machined surface at the top and RBM surface at lower portion were installed in the socket. Stability of the implant was measured with $Osstell^{TM}$ (Model 6 Resonance Frequency Analyser: Integration Diagnostics Ltd., Sweden). After 2 months of healing, the procedures and measurement of implant stability were repeated in the right side by same method of left side. At four months after first experiment, the animals were sacrificed after measurement of stability of all implants, and biopsies were obtained. Results: Well healed soft tissue and no mobility of the implants were observed in both groups. Histologically satisfactory osseointegration of implants was observed with RBM surface, and no foreign body reaction as well as inflammatory infiltration around implant were found. Furthermore, substantial bone formation and high degree of osseointegration were exhibited at the marginal defects around the cervical area of US II plus implants. However, healing of US II implants was characterized by the incomplete bone substitution and the presence of the connective tissue zone between the implant and newly formed bone. The distance between the implant platform (P) and the most coronal level of bone-to-implant contact (B) after 2 months of healing was $2.66{\pm}0.11$ mm at US II implants group and $1.80{\pm}0.13$mm at US II plus implant group. The P-B distance after 4 months of healing was $2.29{\pm}0.13$mm at US II implants group and $1.25{\pm}0.10$mm at US II plus implants group. The difference between both groups regarding the length of P-B distance was statistically significant(p<0.05). Concerning the resonance frequency analysis (RFA) value, the stability of US II plus implants group showed relatively higher RFA value than US II implants group. Conclusion: The current results suggest that implants with rough surface at the cervical area have an advantage in process of bone regeneration on defect around implant placed in a fresh extraction socket.

• 한국지하수토양환경학회지:지하수토양환경
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• 제17권6호
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• pp.33-42
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• 2012

This study was performed to find the problems according to interference factors (organic matter, pH, Cr, Mn, Fe, clay, and etc.) when we analyzed the hexavalent chromium [Cr(VI)] in soils using UV/VIS spectrometer (US EPA 7196A), attempted to evaluate the domestic applicability of analytical method (US EPA 7199) using IC-UV/VIS spectrometer as alternative method. The recovery rate of certified reference materials was 75.0% (US EPA 7196A) and 101.4% (US EPA 7199) by the analytical methods. As the results of performing QA/QC about US EPA 7199, method detection limit (MDL) and limit of quantification (LOQ) were 0.062 mg/kg, 0.196 mg/kg, respectively. The LOQ of US EPA 7199 was lower than that of the current soil official testing method in Korea (0.5 mg/kg). Cr(VI) contents in 23 soil samples were compared by the analytical methods of EPA 7196A and 7199. Cr(VI) was detected in 13 of 23 soil samples by EPA 7196A, while EPA 7199 was not detected in any soil samples. The Cr(VI) content in 23 soil samples by EPA 7196A was not clearly correlated with Cr, Fe, Mn and clay content in the soil samples. However, the contents of Cr(VI) and organic matter of the soil samples had the highest coefficient of determination ($R^2$) of 0.80. In order to evaluate the correlation between the recovery rates of Cr(VI) and organic matter contents in the soil samples, the recovery rates of 5 soil samples added Cr(VI) standard solution were analyzed by the analytical methods. According to the results, the higher the organic matter contents in soil samples, the lower the recovery rates of Cr(VI) by US EPA 7196, while in case of US EPA 7199, the recovery rates were stable regardless of the organic matter contents.

• 대한영상의학회지
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• 제83권4호
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• pp.876-886
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• 2022

목적 MicroPure 초음파 영상의 미세 석회 발견 성능을 평가하고, MicroPure 초음파 영상 소견을 이용하여 미세 석회의 특징을 파악하고자 하였다. 대상과 방법 유방촬영술과 B-mode 초음파에서 모두 보이며, 악성으로 의심되는 총 171개의 미세 석회를 대상으로 MicroPure 초음파 영상을 평가하였다. 미세 석회의 크기는 작거나(점상, 무정형, 미세 다형성, 미세 선형), 큰(거친 불균질) 군으로 구분하였고, 미세 석회의 범위는 좁거나(군집), 넓은(기타) 군으로 나누었다. MicroPure 초음파 영상 가시성은 B-mode와 MicroPure 초음파 영상의 미세석회 개수를 비교하여 4가지로 나누었다: B > M (B-mode에서 더 많은 병변이 보임), B = M (비슷한 개수가 보임), B < M (MicroPure에서 더 많은 병변이 보임), 음성(보이지 않음). MicroPure 초음파 영상의 가시성과 관련된 영상 소견들에 대해 다중비교를 시행하였다. 결과 171개 중 157개의 병변이 MicroPure 초음파 영상에서 확인되었다(91.8%). Breast Imaging Reporting and Data System (이하 BI-RADS) 범주 4A의 비율은 MicroPure 양성군에서 범주 4B의 비율은 MicroPure 음성군에서 유의하게 더 높았다(p = 0.035). 다른 영상 소견에는 차이가 없었다. MicroPure 양성 세부군에서 모든 특징은 유의한 차이를 보이지 않았다. 결론 MicroPure 초음파 영상은 B-mode 초음파에서 보이는 미세 석회의 91.8%를 발견하였다. MicroPure 초음파 영상 가시성은 미세 석회의 범주와 관련이 있었다.

• 경제분석
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• 제27권1호
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• pp.1-36
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• 2021

글로벌 안전자산으로서 미달러화의 위상을 고려할 때 미국 통화정책 등 글로벌 요인은 여타국 금융시장에도 상당한 영향을 미칠 수 있다. 이러한 가설에 대해 본고에서는 미국 통화정책이 국내 채권 및 외환스왑시장에 미치는 영향을 사건연구(event study)를 통해 살펴 보았다. 분석결과, 미국 통화정책은 국내 금리에 유의한 양(+)의 영향을 미치며, 특히 기간프리미엄 비중이 큰 장기물에 보다 큰 영향을 미치는 것으로 나타났다. 시기별로 살펴 보면 금융위기 이전에는 미국 통화정책과 국내 금리 간의 상관관계가 유의하지 않았으나, 위기 이후에는 뚜렷한 양의 관계를 보였다. 또한, 미 연준 통화정책의 기대충격은 우리나라의 단기 및 중기 국고채 금리에, 기간프리미엄충격은 장기 국고채 금리에 크게 영향을 미치는 것으로 분석되었다. 그리고 금융위기 이전에는 미국의 통화정책 충격에 대해 외환 스왑시장의 스왑레이트가 매우 민감하게 반응한 반면 위기 이후에는 유의한 반응을 보이지 않은 것으로 나타났다. 이는 미국의 통화정책 충격이 무위험 이자율 평형에 따라 금융 위기 이전에는 주로 스왑레이트 조정을 통해, 금융위기 이후에는 국내 금리 변화를 통해 국내금융시장으로 파급되었음을 시사한다.

• Korean Journal of Radiology
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• 제24권12호
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• pp.1284-1292
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• 2023

Objective: We investigated the impacts of computed tomography (CT) added to ultrasound (US) for preoperative evaluation of patients with papillary thyroid carcinoma (PTC) on staging, surgical extent, and postsurgical survival. Materials and Methods: Consecutive patients who underwent surgery for PTC between January 2015 and December 2015 were retrospectively identified. Of them, 584 had undergone preoperative additional thyroid CT imaging (CT + US group), and 859 had not (US group). Inverse probability of treatment weighting (IPTW) and propensity score matching (PSM) were used to adjust for 14 variables and balance the two groups. Changes in nodal staging and surgical extent caused by CT were recorded. The recurrence-free survival and distant metastasis-free survival after surgery were compared between the two groups. Results: In the CT + US group, discordant nodal staging results between CT and US were observed in 94 of 584 patients (16.1%). Of them, CT accurately diagnosed nodal staging in 54 patients (57.4%), while the US provided incorrect nodal staging. Ten patients (1.7%) had a change in the extent of surgery based on CT findings. Postsurgical recurrence developed in 3.6% (31 of 859) of the CT + US group and 2.9% (17 of 584) of the US group during the median follow-up of 59 months. After adjustment using IPTW (580 vs. 861 patients), the CT + US group showed significantly higher recurrence-free survival rates than the US group (hazard ratio [HR], 0.52 [95% confidence interval {CI}, 0.29-0.96]; P = 0.037). PSM analysis (535 patients in each group) showed similar HR without statistical significance (HR, 0.60 [95% CI, 0.31-1.17]; P = 0.134). For distant metastasis-free survival, HRs after IPTW and PSM were 0.75 (95% CI, 0.17-3.36; P = 0.71) and 0.87 (95% CI, 0.20-3.80; P = 0.851), respectively. Conclusion: The addition of CT imaging for preoperative evaluation changed nodal staging and surgical extent and might improve recurrence-free survival in patients with PTC.

• Korean Journal of Radiology
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• 제20권5호
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• pp.749-758
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• 2019

Objective: To investigate whether a computer-aided diagnosis (CAD) system based on a deep learning framework (deep learning-based CAD) improves the diagnostic performance of radiologists in differentiating between malignant and benign masses on breast ultrasound (US). Materials and Methods: B-mode US images were prospectively obtained for 253 breast masses (173 benign, 80 malignant) in 226 consecutive patients. Breast mass US findings were retrospectively analyzed by deep learning-based CAD and four radiologists. In predicting malignancy, the CAD results were dichotomized (possibly benign vs. possibly malignant). The radiologists independently assessed Breast Imaging Reporting and Data System final assessments for two datasets (US images alone or with CAD). For each dataset, the radiologists' final assessments were classified as positive (category 4a or higher) and negative (category 3 or lower). The diagnostic performances of the radiologists for the two datasets (US alone vs. US with CAD) were compared Results: When the CAD results were added to the US images, the radiologists showed significant improvement in specificity (range of all radiologists for US alone vs. US with CAD: 72.8-92.5% vs. 82.1-93.1%; p < 0.001), accuracy (77.9-88.9% vs. 86.2-90.9%; p = 0.038), and positive predictive value (PPV) (60.2-83.3% vs. 70.4-85.2%; p = 0.001). However, there were no significant changes in sensitivity (81.3-88.8% vs. 86.3-95.0%; p = 0.120) and negative predictive value (91.4-93.5% vs. 92.9-97.3%; p = 0.259). Conclusion: Deep learning-based CAD could improve radiologists' diagnostic performance by increasing their specificity, accuracy, and PPV in differentiating between malignant and benign masses on breast US.