• Asian Pacific Journal of Cancer Prevention
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• 제15권21호
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• pp.9495-9498
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• 2014

Background: The difference in prognosis of adult and childhood acute lymphoblastic leukemia (ALL) can be attributed largely to variation in cytogenetic abnormalities with age groups. Cytogenetic analysis in acute leukemia is now routinely used to assist patient management, particularly in terms of diagnosis, disease monitoring, prognosis and risk stratification. Knowing about cytogenetic profile at the time of diagnosis is important in order to take critical decisions in management of the patients. Aim and Objectives: To determine the frequency of cytogenetic abnormalities in Pakistani adult patients with ALL in order to have insights regarding behavior of the disease. Materials and Methods: A retrospective analysis of all the cases of ALL (${\geq}15$years old) diagnosed at Aga Khan University from January 2006 to June 2014 was performed. Phenotype (B/T lineage) was confirmed in all cases by flow cytometry. Cytogenetic analysis was made for all cases using the trypsin-Giemsa banding technique. Karyotypes were interpreted using the International System for Human Cytogenetic Nomenclature (ISCN) criteria. Results: A total of 166 patients were diagnosed as ALL during the study period, of which 151 samples successfully yielded metaphase chromosomes. The male to female ratio was 3.4:1. The majority (n=120, 72.3%) had a B-cell phenotype. A normal karyotype was present in 51% (n=77) of the cases whereas 49% (n=74) had an abnormal karyotype. Of the abnormal cases, 10% showed Philadelphia chromosome; t(9;22)(q34;q11.2). Other poor prognostic cytogenetic subgroups were t(4;11)(q21;q23), hypodiploidy (35-45 chromosomes) and complex karyotype. Hyperdiploidy (47-57 chromosomes) occurred in 6.6%; all of whom were younger than 30 years. Conclusions: This study showed a relatively low prevalence of Philadelphia chromosome in Pakistani adults with ALL with an increase in frequency with age (p=0.003). The cumulative prevalence of Philadelphianegative poor cytogenetic aberrations in different age groups was not significant (p=0.6).

• 한국항공우주학회지
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• 제34권3호
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• pp.22-30
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• 2006

본 논문은 초소형 비행체 날개 주위의 공기흐름 조절을 위한 IPMC 작동기로 구동되는 ZNMF 펌프의 체계적인 설계 및 해석 기법을 소개한다. IPMC는 낮은 인가전압에서 큰 굽힘 변위를 발생시키며, 공기 중에서도 작동이 가능하고, 작은 크기로 손쉽게 제작할 수 있기 때문에 소형 펌프의 작동 막으로 매우 적합한 재료이다. 본 연구에서는 수치해석 기법을 이용하여 최대 작동 체적을 발생시키는 IPMC 작동 막의 최적 형상을 찾고, 이러한 최적형상에 기초하여 슬롯을 갖는 ZNMF 펌프를 설계하였다. 이후 초소형 비행체의 비행속도, 펌프 작동 막의 구동 주파수(~ 40 Hz), 슬롯을 통과하는 공기의 속도 등을 이용하여 무차원화 된 진동수와 모멘텀 계수를 구하였고, 설계된 ZNMF 펌프가 초소형 비행체 날개의 공기흐름 조절에 적용이 가능함을 보였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.365-370
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• 2000

A computational study on the effect of sweep angle of axial fan on its noise is performed in the present paper. The forward swept axial fan was designed by numerical optimization method incorporated with three dimensional flow analysis. The objective function was defined by the ratio of generation rate of turbulent kinetic energy to pressure head. And, two variables related with sweep angle distribution are used for design variables. The swept fan has better performance characteristics and noise level. The experimental result shows that spectrums of no-sweet and swept fans have differences in the blade passage frequency, especially in the broadband. And the overall noise level of swept fan is lower 10dB(A) than that of no-sweep fan. For the comparison of flow fields between no-sweep fan and swept fan, CFX-TASCflow computational fluid dynamics software is used. Standard k-${\varepsilon}$ model is used for the turbulence model. Distributions of pressure and turbulent kinetic energy distributions are compared in order to find what happen in the low-noise swept fan.

• 한국소음진동공학회논문집
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• 제13권5호
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• pp.393-399
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• 2003

Hydraulic mounts show strong1y frequency-dependent stiffness and damping characteristics in low frequency range, which result from so called inertia track dynamics. A lumped mass has been incorporated in several mechanical models of the literature to take the inertia effect of the fluid in the track into consideration. Although complex s%illness by the mechanical model showed good agreements with the measured values, there exists a critical pitfall. In this paper, the shortcomings of mechanical models with lumped mass for hydraulic founts are clearly identified by illustrating actual measurements of the stiffness parameters for a hydraulic mount. It is conclusively discussed that the inertia effect of the fluid flow through the circular track is significant but latent. As an alternative to the mechanical model, a hydraulic model is claimed to be used for further dynamic analysis of engine/mount system or whole car system.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2004년도 춘계 학술대회논문집
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• pp.113-118
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• 2004

This paper presents a two-dimensional edge tone to predict the frequency characteristics of the discrete oscillations of a jet-edge feedback cycle by the finite difference lattice Boltzmann method (FDLBM). We use a new lattice BGK compressible fluid model that has an additional term and allow larger time increment comparing the conventional FDLBM, and also use a boundary fitted coordinates. The jet is chosen long enough in order to guarantee the parabolic velocity profile of the jet at the outlet, and the edge consists of a wedge with an angle of $\alpha=23^0$. At a stand-off distance $\omega$, the edge is inserted along the centreline of the jet, and a sinuous instability wave with real frequency f is assumed to be created in the vicinity of the nozzle and th propagate towards the downstream. We have succeeded in capturing very small pressure fluctuations result from periodically oscillation of jet around the edge. That pressure fluctuations propagate with the sound speed. Its interaction with the wedge produces an irrotational feedback field which, near the nozzle exit, is a periodic transverse flow producing the singularities at the nozzle lips. The lattice BGK model for compressible fluids is shown to be one of powerful tool for computing sound generation and propagation for a wide range of flows.

• 전기학회논문지
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• 제59권7호
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• pp.1206-1213
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• 2010

The case that HVDC system is connected to the strong AC network has little the considering problems. However, because there are many problems(example for voltage stability, inertia and low frequency resonance) in case of connecting the weak AC system, a detailed attentions are needed. In particular, because HVDC system can control the flow of AC network freely, have to contain the range of stability and safe operation range. This paper deals with HVDC control algorithms, which are operated within 1 second on viewpoint of time domain, that is, transient stability. The target of HVDC introduced in this paper is Jindo-Cheju HVDC system, which will be operated at 2011. And the introduced algorithm can be actually implemented to Jindo-Cheju HVDC system.

• Wind and Structures
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• 제37권3호
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• pp.191-209
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• 2023

This work investigates the subcritical free-shear prism wake at Re=22,000 by the Koopman analysis using the Dynamic Mode Decomposition (DMD) algorithm. The Koopman model linearized nonlinearities in the stochastic, homogeneous anisotropic turbulent wake, generating temporally orthogonal eigen tuples that carry meaningful, coherent structures. Phenomenological analysis of dominant modes revealed their physical interpretations: Mode 1 renders the mean-field dynamics, Modes 2 describes the roll-up of the Strouhal vortex, Mode 3 describes the Bloor-Gerrard vortex resulting from the Kelvin-Helmholtz instability inside shear layers, its superposition onto the Strouhal vortex, and the concurrent flow entrainment, Modes 6 and 10 describe the low-frequency shedding of turbulent separation bubbles (TSBs) and turbulence production, respectively, which contribute to the beating phenomenon in the lift time history and the flapping motion of shear layers, Modes 4, 5, 7, 8, and 9 are the relatively trivial harmonic excitations. This work demonstrates the Koopman analysis' ability to provide insights into free-shear flows. Its success in subcritical turbulence also serves as an excellent reference for applications in other nonlinear, stochastic systems.

• 지능정보연구
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• 제25권1호
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• pp.1-19
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• 2019

제4차 산업혁명을 이끄는 주요 원동력 중 하나인 인공지능 기술은 이미지와 음성 인식 등 여러 분야에서 사람과 유사하거나 더 뛰어난 능력을 보이며, 사회 전반에 미치게 될 다양한 영향력으로 인하여 높은 주목을 받고 있다. 특히, 인공지능 기술은 의료, 금융, 제조, 서비스, 교육 등 광범위한 분야에서 활용이 가능하기 때문에, 현재의 기술 동향을 파악하고 발전 방향을 분석하기 위한 노력들 또한 활발히 이루어지고 있다. 한편, 이러한 인공지능 기술의 급속한 발전 배경에는 학습, 추론, 인식 등의 복잡한 인공지능 알고리즘을 개발할 수 있는 주요 플랫폼들이 오픈 소스로 공개되면서, 이를 활용한 기술과 서비스들의 개발이 비약적으로 증가하고 있는 것이 주요 요인 중 하나로 확인된다. 또한, 주요 글로벌 기업들이 개발한 자연어 인식, 음성 인식, 이미지 인식 기능 등의 인공지능 소프트웨어들이 오픈 소스 소프트웨어(OSS: Open Sources Software)로 무료로 공개되면서 기술확산에 크게 기여하고 있다. 이에 따라, 본 연구에서는 온라인상에서 다수의 협업을 통하여 개발이 이루어지고 있는 인공지능과 관련된 주요 오픈 소스 소프트웨어 프로젝트들을 분석하여, 인공지능 기술 개발 현황에 대한 보다 실질적인 동향을 파악하고자 한다. 이를 위하여 깃허브(Github) 상에서 2000년부터 2018년 7월까지 생성된 인공지능과 관련된 주요 프로젝트들의 목록을 검색 및 수집하였으며, 수집 된 프로젝트들의 특징과 기술 분야를 의미하는 토픽 정보들을 대상으로 텍스트 마이닝 기법을 적용하여 주요 기술들의 개발 동향을 연도별로 상세하게 확인하였다. 분석 결과, 인공지능과 관련된 오픈 소스 소프트웨어들은 2016년을 기준으로 급격하게 증가하는 추세이며, 토픽들의 관계 분석을 통하여 주요 기술 동향이 '알고리즘', '프로그래밍 언어', '응용분야', '개발 도구'의 범주로 구분하는 것이 가능함을 확인하였다. 이러한 분석 결과를 바탕으로, 향후 다양한 분야에서의 활용을 위해 개발되고 있는 인공지능 관련 기술들을 보다 상세하게 구분하여 확인하는 것이 가능할 것이며, 효과적인 발전 방향 모색과 변화 추이 분석에 활용이 가능할 것이다.

• 한국수자원학회논문집
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• 제40권12호
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• pp.921-930
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• 2007

본 연구에서는 SRES A2 시나리오의 GCM 결과를 역학적으로 다운스케일한 해상도 27km$\times$27km 자료를 이용하여 국내 139개 유역에 대해 기후변화에 따른 수자원의 시공간 변화를 평가하고 결과를 제시하였다. 유출량의 변화는 유역에 따라 그리고 분석기간에 따라 변화율에서 차이가 나타났다. 기간별로 차이는 있으나 한강과 한강동해안에 위치한 유역에서는 연평균유출량이 증가하고 나머지 유역에서는 감소할 것으로 분석되었다. 계절별 분석에서는 가을과 겨울철 유출량의 증가와 봄과 여름철의 유출량이 감소하는 것으로 나타났다. 유역별 유출고를 저수(Q$\leq$5mm), 평수 (5mm$\geq$100mm)으로 구분하여 변화를 분석한 결과, 대부분의 유역에서 2031-2060년과 2061-2090년 기간에서 저수량이 증가하는 것으로 나타났다. 고수량의 경우 기간별로 -100$\sim$500%의 빈도변화를 보여 저수량에 비해 변화율이 큰 것으로 나타났다. 또한 평균유출량의 증감에 관계없이 최대유출량은 시간에 따라 더 커질 것으로 분석되었다. 유역별 연평균 기온, 강수 그리고 유출변화율을 이용하여 추정한 회귀분석 결과 기온이 1$^{\circ}C$ 변화함에 따라 권역별로 실제증발산이 3.4$\sim$5.3% 정도 변화되는 것으로 나타났다. 이 상황에서 강수량이 $\pm$10% 변화 될 경우 유출량이 권역별로 -18.2$\sim$+12.4%(한강), -21.6$\sim$+14.6%(낙동강), -17.5$\sim$+11.5%(금강), -18.4$\sim$+10.6%(섬진강), -19.9$\sim$+12.7%(영산강)의 변화를 보일 것으로 분석되었다.

• 한국농공학회논문집
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• 제58권6호
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• pp.93-100
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• 2016

This study conducted a quantitative assessment on the environmental flows associated with climate change in the Gosam Reservoir, Korea. The application of RCP 8.5 climate change scenario has found that the peak value of High Flow Pulses has increased by 36.0 % on average compared to historical data (2001 ~ 2010), which is likely to cause disadvantage on flood control and management but the increase in peak value is expected to make a positive impact on resolving the issue of green algal blooms, promoting vegetation in surrounding areas and encouraging spawning and providing habitats for native species by releasing a larger amount of landslides as well as organic matters than the past. However, the decreasing pattern of the peak value of High Flow Pulses is quite apparent with the trend of delay on the occurrence time of peak value, necessitating a long-term impact analysis. The peak value of Large Floods shows a clear sign of decrease against climate change scenario, which is expected to lead to changes in fish species caused by degraded quality of water and decreasing habitats. A quicker occurrence of Small Floods is also expected to make an impact on the growth cycle of aquatic plants, and the reduction in occurrence frequency of Extreme Low Flows is to contribute to increasing the population of and raising the survival rate of native fish, greatly improving the aquatic ecosystem. The results of this study are expected to be useful to establish the water environment and ecological system in adapting or responding to climate change.