• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
• /
• pp.221-223
• /
• 2003

The tidal bores of the Qiantang River on the East coast of China are simulated numerically based on the shallow water theory. The governing equations, which were traditionally formulated using water depth, are formulated in terms of water surface level, and the fractional-step method is applied in conjunction with a Godunov-type scheme. In addition, the source terms due to bottom gradient are discretized centrally to exactly balance the flux terms. Our numerical simulation produces tidal bores in excellent agreement with field measurements.

• Journal of Hydrospace Technology
• /
• 제2권2호
• /
• pp.57-67
• /
• 1996

The formulation for hybrid-QUICK scheme of convective transport terms in finite-volume calculation procedure is presented. Source terms are modified to apply the hybrid-QUICK scheme. Test calculations are performed for wall-driven cavity flow at Re=$10_2$, $10_3$, and $10_4$. These include the evaluation of boundary conditions approximated by third-order finite difference scheme. The stable and converged solutions are obtained without unsteady terms in the momentum equations. The results using hybrid-QUICK scheme show no difference with those using hybrid scheme at low Re ($=10_2$) and are better at higher Re ($10_3$, and $10_4$).

• Genomics & Informatics
• /
• 제17권2호
• /
• pp.16.1-16.4
• /
• 2019

Medical Subject Headings (MeSH), a medical thesaurus created by the National Library of Medicine (NLM), is a useful resource for natural language processing (NLP). In this article, the current status of the Japanese version of Medical Subject Headings (MeSH) is reviewed. Online investigation found that Japanese-English dictionaries, which assign MeSH information to applicable terms, but use them for NLP, were found to be difficult to access, due to license restrictions. Here, we investigate an open-source Japanese-English glossary as an alternative method for assigning MeSH IDs to Japanese terms, to obtain preliminary data for NLP proof-of-concept.

• 한국언론정보학보
• /
• 제30권
• /
• pp.175-201
• /
• 2005

본 논문은 '다양성'이라는 규범적 가치에 입각해 뉴스 기사 선별 및 취재 경로와 관련한 미 신문의 뉴스 제작 방식에는 어떤 변화가 진행돼 왔는지를 통시적으로 살펴보고 있다. 이에 따라 본고에서는 '뉴스 토픽'과 '정보원' 등 두 가지 분야에서 지난 50년간 뉴욕 타임스와 시카고 트리뷴, 로스앤젤레스 타임스 등 3대 유력 일간지의 1면 기사를 분석, 연대기적인 가치 변화를 추적해 보았다. 데이터 분석 결과, 지난 반세기 동안 미 신문에서 정부 및 정치권에 대한 정보원의 의존도는 지속적으로 줄어들고 있는 반면, 기업/산업체발 정보원의 등장은 점차 빈번해 지고 있는 것으로 나타났다. 이와 함께, 뉴스 주제의 분포에 있어서는 사건, 사고 기사의 감소와 군사, 안보기사의 퇴조 속에, 경제, 건강, 교육 등과 같은 주제가 점차 활발하게 다뤄지고 있는 것으로 조사됐다. 그러나 전통적인 비인기 주제였던 빈곤, 노동, 소수자, 사회 갈등 등과 같은 토픽들은 시대를 거듭해도 제자리를 맴돌거나 오히려 줄어들고 있는 것으로 나타났다.

• 비파괴검사학회지
• /
• 제3권2호
• /
• pp.5-12
• /
• 1984

The purpose of this paper is to decide volume of crack by AE source wave analysis. The material studied in this paper was Titanium Alloy. Transient wave memory has 50 nano sampling time. The response function of specimens and transducer was obtained experimentally by use of specimens and transducer was obtained experimentally by use of breaking pencil lead as a reference simulated AE source, and the source waves were dertermined in terms of energy release-time functions explicitly through a time domain deconvolution. From experimental results, we can determine size of cracked volume.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 춘계학술대회논문집
• /
• pp.85-89
• /
• 2001

The problem of the transient interaction of a plane acoustic shock wave which has an infinitely steep wave front with a cylindrical or spherical elastic shell has been studied analytically from early fifties based on the integral transform and series solution techniques. Huang adopted an inverse Laplace transform, and used a finite number of terms of the infinite series expansion of the equations for the shells. In the 1990s, the results have been used by many authors for validation of computer codes. The object of this paper is to discuss the interaction between a moving source and submerged spherical shells. Since the center of source is moving the first contact location between the waves and shell changes depending on the source velocity and distance. These are considered in the analysis. Furthermore, constant source strength and decreasing strength are considered in the analysis. Radial velocities at several locations on the structure are obtained and the results are discussed.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2004년도 추계학술대회 논문집
• /
• pp.64-69
• /
• 2004

This paper deals with an algorithm for controlling ac output voltage of Z-source inverter using Modified SVPWM (abbreviated as MSVPWM). Unlike the conventional space vector pulse width modulation, MSVPWM has one extra shoot-through zero time $T_{sh}$. During shoot-through zero time, both switches in a leg are conducted simultaneously in order to boost inverter output voltage to any desirable value regardless the line voltage. The algorithm to control linearly the capacitor voltage is suggested to improve the performance of Z-source inverter system. The performance of Z-source inverter using above algorithms is demonstrated in simulation results using PSIM. Index terms-Z-source inverter (ZSI), shoot-through time, three-phase carrier-based PWM, space vector PWM (SVPWM), modified space vector PWM (MSVPWM).

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2001년도 전력전자학술대회 논문집
• /
• pp.565-568
• /
• 2001

A novel control scheme compensating for source voltage unbalance and harmonic current for series active power filters is proposed, where the references for voltage unbalance and current harmonic and phase angle is derived from the positive sequence component of the source voltage obtained simply through digital all-pass filters, which makes the whole control algorithm simpler than other methods using p-q theory. In addition, the harmonic component of source current is compensated by harmonic component of load voltage and therefore fundamental component of source current is considered as separated terms for the control issue. The validity of the proposed scheme has been verified by experimental results.

• 설비공학논문집
• /
• 제18권4호
• /
• pp.344-350
• /
• 2006

The present study investigates the characteristics of fire-driven heat flows and gas concentration in a compartment fire by using the modified VHS model (MVHS). The main idea of this model is to add some source terms for combustion products and oxygen consumption to the original VHS model for providing more accurate and useful information on gas concentration distributions as well as thermal fields. It is found that the present MVHS model shows fairly good agreement with the experimental data and the eddy breakup combustion model. The tilting angle of fire plume calculated by MVHS is larger than that of EBU model because the fire source of VHS is affected by ventilating flow less than EBU. However, this discrepancy is apparently reduced in the downstream region of fire source.

• 한국해양공학회지
• /
• 제33권5호
• /
• pp.421-426
• /
• 2019

The directivity of an underwater sound source should be measured in an acoustically open field such as a calm sea or lake, or an anechoic water tank facility. However, technical difficulties arise when practically implementing this in open fields. Signal processing-based techniques such as a sound intensity method and near-field acoustic holography have been adopted to overcome the problem, but these are inefficient in terms of acquisition and maintenance costs. This study established a simple directivity estimation technique with data acquisition, filtering, and analysis tools. A numerical simulation based on an acoustic radiosity method showed that the technique is practicable for sound source directivity estimation in a diffused reverberant acoustic field like a reverberant water tank.