• 한국정보전자통신기술학회논문지
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• 제14권5호
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• pp.375-384
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• 2021

유럽철도교통관리시스템(ERTMS, European Railway Traffic Management System) 개발은 1989년 유럽의 단일화된 상호호환성을 갖춘 철도노선 구축을 위해 유럽연합 정책의 일환으로 시작되었으며, 철도신호시스템은 유럽의 ERTMS/ETCS(European Train Control System)가 국제적으로 표준화가 되어 가고 있는 추세이다. 이에 대한 해결책으로 국내 열차제어 분야도 상호호환성을 고려한 열차제어시스템의 기술개발이 보다 더 필요한 시점이다. 유럽철도국(ERA, European Railway Agency)에서는 2020.12.31 이후 신규 ETCS 장착열차에 대해서 B3R2(Baseline 3 Release 2)를 제시하고 있으며 우리나라는 경부선, 호남선, 전라선, 경춘선에서 Baseline 2.2.0부터 2.3.0까지 설치되어 운영 중이다. 계속되는 Baseline의 upgrade에 따라 기술적인 검토사항과 경제적인 고려사항이 발생하고 있는 추세이다. 본 논문에서는 현재 배포된 최신의 유럽 표준 ERTMS/ETCS Baseline 3에 대한 주요기능 및 상호호환성을 분석하고, 향후 국내 KTCS(Korean Train Control System)의 Baseline 적용방안을 제시하고자 한다.

• 한국통신학회논문지
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• 제34권12C호
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• pp.1154-1166
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• 2009

본 논문에서는 다시점 동영상을 이용한 기저선(baseline)상의 가상시점 영상 생성과 기저선상 외의 가상시점 영상 생성을 위한 기법을 제안한다. 제안한 기법에서는 가상 시점을 생성하기 위하여 영상의 깊이(depth)정보와 고정된 카메라의 기하학적 특성을 이용한 3차원 워핑(warping) 방법을 적용한다. 영상의 실제 3차원 좌표는 영상의 깊이 정보와 카메라의 기하학적 특성을 이용하여 산출되고, 산출된 3차원 좌표는 임의 위치의 가상 카메라에 투영(projection)되어 2차원의 가상 시점 영상이 생성된다. 제안한 방법에 의해 생성된 기저선상의 중간시점 영상은 기존의 방법으로 생성된 중간시점 영상보다 PSNR이 0.5dB 이상 향상된 결과를 나타내었고, 기저선상 외의 가상 시점 영상에서 나타나는 많은 미처리 영역을 보다 효과적으로 처리하여 가상시점 영상을 생성할 수 있었다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권1호
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• pp.293-297
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• 2013

Background: : Chemotherapy-induced thrombocytopenia (CIT) is an important cause of morbitity in patients with cancer. Aim: To investigate the effect of the baseline plasma D-dimer level, an important marker for thrombotic activity, on chemotherapy-induced thrombocytopenia in patients with stage III colon cancer. Materials and Methods: A total of 43 (28 men) eligible patients were divided into two groups according to whether they exhibited chemotherapy-induced thrombocytopenia: Group 1 (n=21) and Group 2 (n=22). Comparison was made using demographic, histopathologic, and laboratory variables. Additionally, baseline plasma D-dimer levels underwent receiver operation characteristics curve analysis, and areas under the curve were calculated. Sensitivity, specificity, and positive and negative likelihood rates were then determined. Results: The incidence of chemotherapy-induced thrombocytopenia had a significant correlation with baseline platelet count (r=0.568, P=0.031) and baseline plasma D-dimer levels (r=0.617, P=0.036). When the cut-off point for the latter was set as 498 ng/mL, the area under the curve was 0.89 (95%CI: 0.74-0.93), the sensitivity was 91.4%, the specificity was 89.7%, the positive likelihood rate was 3.64 and the negative likelihood rate was 0.24 for chemotherapy-induced thrombocytopenia diagnosis. Conclusions: The baseline level of plasma D-dimer could help to differentiate high-risk patients for chemotherapy-induced thrombocytopenia.

• 한국통신학회논문지
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• 제31권10A호
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• pp.988-995
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• 2006

본 논문에서는 방위각과 고각을 동시에 탐지하는 2차원 멀티베이스라인 센서 배열 설계에서 DOA(Direction Of Arrival) 정확도를 유지하면서 센서 안테나수를 최소화하기 위해 위상차 공간에서 유클리드 최소 거리함수를 이용한 논하모닉 배열 구조 설계 메소드를 제안한다. 제안된 메소드는 기존 메소드와 달리 최소 이격 거리비가 반파장 이상인 경우에도 적용 가능할뿐더러 임의 배열구조에서도 적용이 가능한 장점을 갖는다. 다중신호 입사조건에서 초분해능 알고리즘을 적용한 모의 실험을 통해 설계 접근성의 효율성을 제시하였다. 또한 제안된 메소드를 적용하여 2차원 비대칭 배열 안테나를 설계하였고, 제작된 배열 안테나를 이용한 실험 결과를 통해 그 성능을 확인하였다.

• Journal of information and communication convergence engineering
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• 제6권1호
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• pp.29-33
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• 2008

This paper presents the proposal and hardware design of JPEG baseline encoder. The JPEG encoder system consists of line buffer, 2-D DCT, quantization, entropy encoding, and packer. A fully pipelined scheme for JPEG encoder is adopted to speed-up an image compression. The proposed architecture was described in VHDL and synthesized in Xilinx ISE 7.1i and simulated by modelsim 6.1i. The results showed that the performance of the designed JPEG baseline encoder is higher than that demanded by real-time applications for $1024{\times}768$ image size. The designed JPEG encoder IP can be easily integrated into various application systems, such as scanner, PC camera, color FAX, and network camera, etc.

• Progress in Superconductivity
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• 제9권1호
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• pp.45-49
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• 2007

We have investigated the optimum combination of the environmental noise condition and type of SQUID pickup coil in order to obtain maximum signal-to-noise ratio (SNR). The measurement probe consists of 1st order gradiometer with pickup coils of 100 mm, 70 mm, and 50 mm baseline length, a 2nd order gradiometer with 50 mm baseline, and a magnetometer. The pickup coils are fabricated by winding Nb wire on a bobbin with 200 mm diameter. Noise and heart signal of a healthy male were measured by various SQUID sensors with different types of pickup coils in various magnetically shielded rooms (MSR), and compared to each other. The shielding factors were found to be 43 dB, 35 dB and 25 dB at 0.1 Hz for MSR-AS, MSR-BS, MSR-CS, respectively. White noises were $3.5\;fT/Hz^{1/2}$, $4.5\;fT/Hz^{1/2}$ and $3\;fT/Hz^{1/2}$ for the 1st order gradiometers, the 2nd order gradiometers, and magnetometer for all MSRs. SNR of the magnetometer was up to 56 dB in MSR-AS, while the 1st order axial gradiometer with 70 mm baseline length was up to 54 dB in MSR-BS. The 2nd order axial gradiometer with 50 mm baseline length of pickup coil was found to be up to 40 dB in MSR-CS.

• Nutritional Sciences
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• 제9권1호
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• pp.42-47
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• 2006

It has been reported that taking a proper amount of calcium and vitamin D helps to increase bone mineral density (BMD) and is effective in decreasing the risk of osteoporosis. This study investigated the supplementary effects of calcium and vitamin D on postmenopausal women who had osteoporosis and used calcium and vitamin D supplements. The study subjects consisted of osteoporotic postmenopausal women who were recruited from the Department of Orthopedics in a university-affiliated hospital. Sixty-seven study subjects were orally administrated 1,000 mg of calcium (calcium carbonate) and 2.5 mg of active vitamin D (1-$\alpha$ hydroxyvitamin D) (cholecalciferol 250 IU) twice a day for a year and a half. BMD and biochemical markers were evaluated and repeated every six months. One year after the intervention test, the bone mineral density of the lumbar spine was significantly increased as compared to the baseline. Six months after supplement administration, the level of serum alkaline phosphatase began to decrease, and afterwards a significant difference was maintained Concentration of 1, 25-dihydroxy-vitamin D at 1.5 years was higher than that of the baseline. In comparison with that of the baseline, the level of urinary hydroxyproline in the study subjects over six months was significantly decreased This study continued that effects such as BMD improvement and changes in biochemical markers appeared at least one year after administration of supplements.

• 한국군사과학기술학회지
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• 제25권2호
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• pp.135-143
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• 2022

In this paper, the compact waveguide slot array antenna for interferometric radar altimeter is proposed. The proposed antenna structure consist of corrugation structure which is applied between each channel to improve isolation, three-channel waveguide slot array antenna and feeder. In addition, to reduce the occurrence of phase ambiguity, the baseline spacing of the three-channel antenna is analyzed and the results are applied to the design. For compact design, reduced height and SMP connector structure are used and the dip brazing method which is the conjugation method after dipping to flux is used for the fabrication of the lightweight antenna. The measurement result of the proposed antenna shows less than 1.41 : 1 (VSWR) and 48.3 dBc (isolation). The antenna gain is higher than 20.2 dBi and the side lobe levels are lower than 18.8 dB (vertical plane) and 10.0 dB (horizontal plane).

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제20권1호
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• pp.41-46
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• 2017

Purpose: Vitamin D deficiency is common in Crohn disease (CD). The aim of the study was to examine the prevalence of vitamin D deficiency and evaluate the association between vitamin D status and growth outcome in Korean pediatric CD patients. Methods: In this retrospective study, 17 children younger than 18 years old diagnosed with CD were enrolled and their serum 25-hydroxy vitamin D (25[OH]D) was checked between 2011 and 2015. We categorized the patients into two groups, Group 1 and Group 2. Group 1 included patients with serum 25(OH)D levels below 10 ng/mL, and Group 2 was for patients with a 25(OH)D serum levels between 10 ng/mL and 30 ng/mL. The z-scores for height (Htz), weight (Wtz), and body mass index (BMIz) were measured at baseline, 6 months, and 12 months. Results: The mean serum 25(OH)D levels of the total 65 CD patients and 17 enrolled patients were $15.64{\pm}6.9ng/mL$ and $13.1{\pm}5.1ng/mL$, respectively. There was no correlation at the beginning of the study between vitamin D level and growth parameters (Htz, Wtz, BMIz) or other variables including laboratory data and Pediatric Crohn Disease Activity Index. The Htz, Wtz, and BMIz in Group 1 showed no significant improvement at 6 months and 12 months follow-up. In Group 2, Wtz and BMIz showed significant improvements sustained until 12 months of follow-up. Htz showed no significant improvement at 6 months but there was significant improvement at 12 months. Conclusion: It seems that baseline vitamin D status affects growth outcome in pediatric CD.

• 한국측량학회지
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• 제18권2호
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• pp.121-127
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• 2000

단시간 관측으로 많은 3차원 지형정보를 획득할 수 있는 GPS 이동측량은 수 km 이하의 단기선에서 주로 활용되고 있으며, 장기선에 대한 위치결정은 비교적 오랜 시간이 요구되는 정지 측량에 의존하고 있어 단시간으로 장기선 위치결정을 할 수 있는 방법이 요구되고 있다. 본 연구는 장기선에 대한 GPS 이동측량의 적용가능성을 검토하기 위하여 수 십 km 이상의 기선에 대한 기선거리별, 궤도력별 그리고 관측시간대별로 GPS 이동측량의 기선해석 정확도를 정지측량 결과와 비교ㆍ분석하고자 한다. 연구결과, PDOP이 4이하로 매우 양호한 경우 기선길이 약 60 km이하에서 신속정밀궤도력을 이용하면 수 분의 GPS측량으로 3차원 지형정보 획득이 가능할 것으로 기대되며, IGS의 최종 정밀궤도력을 적용한 경우와 유사한 정확도 획득이 가능함을 알 수 있었다. 앞으로 장기선 GPS 이동측량에 대한 더욱 심도 있는 연구가 진행된다면 국토개발을 비롯한 각종 건설분야에 필요한 지형정보를 보다 효율적으로 획득할 수 있을 것으로 기대된다.