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디지털 영상의 표현 층위 고도화와 기술 환경 - 90년대 초 고(高) 부동소수점 연산 성능의 보급과 CG/CGI 작업물의 관계를 중심으로
윤나라 ( Yoon¸ Na-ra ) 한국기호학회 2022 기호학연구 Vol.70 No.-
이 글은 융합적 담론의 저변 확대를 통해 인문학 연구자뿐만 아니라 콘텐츠 창작자와 기술 개발 당사자 모두가 공유할 수 있는 공통 기반의 수립에 기여함을 목표로 한다. 이를 위해, 이 글은 창작과 비평, 기술과 예술 모두에서 공히 빈번하게 다루어지는 컴퓨터 그래픽스(Computer graphics, CG) 및 컴퓨터 생성 이미지(Computer generated imagary, CGI) 분야와 이 분야에서 가장 중요한 지표 중 하나인 부동소수점 연산 성능을 중심으로 융합적 논의의 가능성을 타진한다. 디지털 영상 작업은 가장 바깥쪽의 시각적 층위 한 겹을 제외하면 표현식의 작성과 조작, 즉 수학적 데이터를 다루는 행위이며, 따라서 데이터의 정확도 및 정밀도와 밀접한 관련이 있다. 소수점이 유동(流動)하는 부동소수점 방식은 고정소수점 방식에 비해 더 적은 자릿수만으로도 더 넓은 범위의 수를 더 정확하고 더 정밀하게 표현할 수 있지만, 소수점의 유동성으로 인해 더 높은 연산 성능을 필요로 한다. 1990년대 초반 저비용 고성능의 범용 하드웨어의 등장과 보급은 새로운 기술 환경을 조성했고, 이는 곧 디지털 영상 작업물의 고도화뿐만 아니라 대중화도 함께 견인했다. 이 글은 당시의 상황을 기술과 예술의 융합적 관점을 통해 재조명하고자 한다. 이 과정에서, 이 글은 공학과 수학의 전문 용어를 사용하는 대신 ‘글(또는 말)로 풀어 설명하기’의 방식을 채택할 것이며, 그렇게 함으로써 인문학의 방식으로도 문화예술과 정보기술의 상호작용에 관한 실질적인 담론이 가능한지를 실험한다. This article aims to ponder the lack of competitiveness and the impracticality of interdisciplinary research on art as well as on information technologies. The concept of floating point system and FLOPS is important, because all VFX CG/CGI workflow except its surface or “most superficial layer” is fundamentally writing mathematical formulas and manipulating mathematical data. Although the floating point system offers more precision and accuracy, it requires more computing power than the fixed point system. In the early 1990s, low-cost and high-performance general-purpose hardware such as Intel’s Pentium™ processor offered significantly more FP performance or “FLOPS” than before. Such a leap in performance led not only to the advent of a renewed technological environment, but also to the sophistication of VFX CG/CGI workflows, and ultimately, to the declination of a company such as SGI. This article is an experimental attempt that tries to re-examine the then situation not through another traditional point of view, but through a contemporary interdisciplinary one.
Release of Sr From Sr-Coprecipitated Calcite Under Various Environment Conditions
Nara Jeong,Wooyong Um 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.2
Concrete is used as the main engineering barrier in low and intermediate level radioactive waste disposal facilities. As the time passed, the radionuclides stored in repository may contact with groundwater and leak into the ecosystem through the rock media. In this process, the radionuclides can react with calcite via sorption or coprecipitation, because calcite is the major mineral of concrete. Under the various background conditions in repository, frequent dissolution-precipitation reactions can happen. Dissolution of Sr-coprecipitated calcite may be different from that of SrCO3(s) which can mislead the safety performance of radioactive Sr and the estimate of Sr mobility based on the solubility of SrCO3(s). Strontium is not only one of the fission products but also emits beta rays with a long half-life almost 29 years. The strontium may be released or retarded by the dissolution-precipitation reactions in repository. In this study, the dissolution of Sr-coprecipitated with respect to calcite was tested in various environment conditions. The Sr-coprecipitated calcite, (Sr,Ca)CO3(s) was synthesized by coprecipitation method in alkaline condition. The 250 mL of 0.1 M of CaCl2 solution was mixed with 250 mL of 1.14 mM SrCl2·6H2O solution. Then, independently prepared 500 mL of 0.1 M Na2CO3 solution was mixed with the mixed solution of CaCl2 and SrCl2. The precipitates could be made and they were aged for 3 days at room temperature. Then, the supernatant was separated by the centrifugation and the solid at the bottom was dried in an oven at temperature 80°C. After that, the Srcoprecipitated calcite powder was washed using the DI water several times and dried again before use. Characterization of solid powder was conducted by XRD and SEM, and the ICP-MS and ICP-AES were used to analyze the concentrations of Ca and Sr. The batch dissolution experiment was conducted with a solid-to-solution ratio of 10 g/L groundwater in polyethylene tubes. The oxidative groundwater was synthesized by simulating the chemical composition of KAERI Underground Research Tunnel (KURT) DB-3 groundwater. Different temperatures and pHs were prepared and tested for the release of Sr and Ca from the coprecipitated (Sr,Ca)CO3(s) to compare the results with the release of Sr and Ca from SrCO3(s) and CaCO3(s), respectively. Such as, these results will be used to provide better understanding of Sr release and mobility in various repository environments.
Subcritical crack growth in rocks in an aqueous environment
Nara, Yoshitaka,Takada, Masafumi,Igarashi, Toshifumi,Hiroyoshi, Naoki,Kaneko, Katsuhiko Korean Society of Earth and Exploration Geophysici 2009 지구물리와 물리탐사 Vol.12 No.1
임계하 균열성장(subcritical crack growth)은 암석 내에서 오랜 시간 동안 일어나는 균열시스템 발달의 주된 원인으로 그 중요성이 매우 크다. 본 연구에서는 증류수(pH = 5-7)와 수산화나트륨(NaOHaq, pH = 12)용액으로 포화된 암석과 건조암석에서의 임계하 균열성장에 대해 고찰하였다. 아울러 공극유체의 수소이온농도(pH)의 영향도 함께 살펴보았으며, 안산암과 화강암이 연구에 사용되었다. 연구방법은 온도가 조절된 환경에서 이중-비틀림 실험(double-torsion test)을 실시하여 균열성장속도와 응력확장계수와의 상관관계를 파악하였다. 연구의 결과 수성환경에서 균열성장속도가 건조한 경우보다 크게 나타났으며, 이는 기존 연구에서 물이 첨가되었을 때 균열성장속도가 빨라지는 결과와 잘 일치한다. 증류수와 수산화나트륨 사이의 결과에서는 수소이온농도의 차이에도 불구하고 균열성장속도의 차이가 나타나지 않았으며 이는 수산화이온이 균열성장을 가속한다는 기존의 결과와는 차이를 보였다. 따라서 균열의 첨단부(crack-tip)에서의 수소이온농도의 차이는 균열의 성장에 영향을 미치지만, 공극유체의 전체적인 수소이온농도(bulk pH)의 영향은 매우 적다는 결론을 얻을 수 있었다.
Narae Kang,Yonsoo Kim,Hui Seung Noh,Hung Soo Kim 한국방재학회 2016 Journal of Disaster Management Vol.1 No.4
Rainfall has recently begun to show different properties in space and time. In particular, although localized heavy rainfall is frequent, rain gauges on the ground can only observe rainfall at one point. In other words, ground-based rain gauges have limitations in spatial and temporal resolution for measuring rainfall. As a result, there is a need to utilize radar rainfall measurements that can consider the spatial distribution of the change in rainfall based on the direction of the storm. In this study, we tried to apply radar rainfall for a runoff simulation of an urban drainage system. The study area was Guro-gu, Seoul City, Korea, and we divided the study area into sub-basins based on the rain gauge network of the AWS (Automatic Weather Station). Then, the radar rainfall data were adjusted using the rainfall data of the rain gauge stations, and the areal rainfall amounts were obtained. The runoffs were simulated using the XP-SWMM model in the sub-basins of an urban drainage system. As a result, the adjusted radar rainfalls underestimated the ground-based measurement data by 60 to 95%. Therefore, differences in runoffs simulated by the adjusted radar and the gauge rainfall amounts are found. The peak runoff time from the radar rainfall occurred earlier than that from the gauge rainfall. This result is due to the fact that the radar rainfall can reflect the spatial variability of the rainfall in time by taking into consideration the movement of a storm.
Survival and pattern of Recurrence in Bevacizumab for advanced cervical cancer
( Nara Lee ),( Seik Kim ),( Jaehyun Cho ),( Maria Lee ),( Hee Seung Kim ),( Hyun Hoon Chung ),( Jae Weon Kim ),( Noh Hyun Park ),( Yong Sang Song ) 대한산부인과학회 2018 대한산부인과학회 학술대회 Vol.104 No.-
Objective: To evaluate the efficacy and pattern of recurrence of bevacizumab and chemotherapy in persistent, recurrent, or metastatic cervical cancer. Methods: We retrospectively reviewed medical records of 1) patients with persistent, recurrent, or metastatic cervical cancer treated at SNUH from 2014.4 to 2018.2 and 2) all patients for treatment with cisplatin plus paclitaxel and bevacizumab every 3 weeks until disease progression or unacceptable toxic effect or complete response. Results: Of 57 patients, 36 (63%) patients had recurrent disease, 7(12.3%) patients had persistent and 14 (24.6%) had metastatic disease at treatment. The prior exposition to platinum was 29 (50.9%). Grade 3 or 4 adverse events possibly related to bevacizumab included hypertension (n= 3, 5.3%), febrile neutropenia (n= 4, 7%), or fistula (n=1, 1.8%). During follow-up, there were 21 deaths(36.8%) and 24 recurrence (42.1%) (distant n=10, 41.7%, locoregional n=13, 54.2%, or peritoneal seeding n=5, 20.8%), nodal(n=10, 41.7%). The median PFS and OS were 6.64 and 18.20 months, respectively. Conclusion: This study can provide useful information about clinical efficacy and recurrence pattern of bevacizumab combined with chemotherapy about patients with recurrent, persistent or metastatic cervical cancer.