• Journal of Ocean Engineering and Technology
• /
• v.24 no.3
• /
• pp.31-37
• /
• 2010

During typhoon periods, coastal regions are often directly flooded by typhoon-surges. There are also many cases where coastal regions are inundated by river inundations or dam breaks. However, most studies on coastal flooding by typhoons have been restricted to cases involving the sea. Flooding by river inundation has been excluded in those studies. Usually ocean numerical models are not applied to river flow because the governing equations for ocean flow and river flow are not the same. For a coastal flooding simulation with river inundation, POM, the three-dimensional numerical ocean model, was applied to the popular river flow problems, dam-break problem, and flows over a spillway. The simulated results showed good agreement with other numerical simulations and measured data, suggesting the possibility of using POM in coastal flooding simulations involving direct coastal surges and river inundations.

• Journal of the Korean Society of Safety
• /
• v.26 no.6
• /
• pp.124-129
• /
• 2011

The purpose of this study was to examine the effects of goal-setting on Eco-driving behaviors. An additional purpose was to examine whether setting goals on target behaviors had spread effects on non-target eco-driving behaviors. Three office workers who drive regularly participated in this study. An AB multiple baseline design was adopted. After baseline (A), participants set goals on two or three target behaviors(e.g., over speeding, put the gears in neutral, extreme acceleration) (B). Results showed that goal-setting was effective in increasing the targeted eco-driving behaviors. In addition, most of the non-target eco-driving behaviors(e.g., extreme break, extreme acceleration) increased.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.10 no.6
• /
• pp.95-101
• /
• 2011

Micro-abrasive jet machining(${\mu}AJM$) using mask is a fine machining technology which can carve a figure on a material. The mask should have holes exactly same as the required figure. Abrasive particles are jetted into the holes of the mask and it collide with the material. The collision break off small portion of the material. And the ${\mu}AJM$ nozzle should move all over the machining area. However, in general the carving shape is modeled as in a bitmap figure, because it often contains characters. And the mask model is also often modeled from the bitmap image. Therefore, the machining path of the ${\mu}AJM$ also efficient if it can be generated from the bitmap image. This paper suggest an algorithm which can generate ${\mu}AJM$ tool path directly from the bitmap image of the carving figure. And shows some test results and applications.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.05a
• /
• pp.264-267
• /
• 2010

This research focuses on the development of numerical code to deal with compressible two phase flow around three dimensional objects combined with cavitation model suggested by Weishyy et al. with k-e turbulent model. The cryogenic cavitation is carried out by considering the thermodynamic effect on physical properties of cryogenic fluids in physical point of view and implementing the temperature sensitivity in the energy equation of the government equations in numerical point of view, respectively. The formulation has been extensively validated for both liquid nitrogen and liquid hydrogen by simulating the experiments of Hord on hydrofoils. Then, simulations of cavitating turbopump inducers at their design flow rate are presented. Results over a broad range of Nss numbers extending from single-phase flow conditions through the critical head break down point are discussed. In particular, thermal depression effects arising from cavitation in cryogenic fluids are identified and their impact on the suction performance of the inducer quantified.

• Journal of the Korean Society of Safety
• /
• v.3 no.1
• /
• pp.31-36
• /
• 1988

We live in the building which made of concreat. If a fire break out in the building on a sudden, the heated concreat structual of the building were become very weak and bad poor. In this study, it was investigated by test for thermal expansibility and compressive strength of the highly heated concreat. The experiment was carried out in the temparature range of 150―75$0^{\circ}C$. The obtained results are as follow. 1. The heated concreat has weaken in compressive strength from about at 30$0^{\circ}C$. 2. The concreat heated over 45$0^{\circ}C$ is not proper for structual material. 3. The concreat expanded remarkable when it was heated about at 450―$600^{\circ}C$.

• Industrial Engineering and Management Systems
• /
• v.11 no.1
• /
• pp.11-17
• /
• 2012

Along with the recent trend toward increasing variety and shorter life of products in the market, evaluation of risk for economic investment alternatives is of practical importance in manufacturing companies. This paper assumes that each alternative is composed of demand volume and unit sales price as income factors, and unit variable cost and fixed cost as expense factors. The paper assumes that these four factors move worse from the originally expected values, toward the direction of decreasing profit. Values of these four factors are also assumed to fluctuate from year to year over the entire multi-period. By applying the analysis of the breakeven points to each of the four factors, safer area against these changes is represented on the two dimensional domain called normalized total-cost unit-cost domain. A practical numerical example is analyzed to verify the validity of the proposed method.

• Nuclear Engineering and Technology
• /
• v.39 no.1
• /
• pp.75-84
• /
• 2007

This paper presents a closed-form model for evaluating the restraint effect of pressure induced bending on the opening of a circumferential through-wall crack, which is considered plastic deformation behavior. Three-dimensional finite element analyses with different crack lengths, restraint conditions, pipe geometries, magnitudes of internal pressure, and tensile properties were used to investigate the influence of each parameter on the pressure-induced bending restraint on the crack opening displacement. From these investigations, an analytical model based on elastic-perfectly plastic material was developed in terms of the crack length, symmetric restraint length, mean radius to thickness ratio, axial stress corresponding to the internal pressure, and normalized crack opening displacement evaluated from a linear-elastic crack opening condition. Finite element analyses results demonstrate that the proposed analytical model reliably estimated the restraint effect of pressure-induced bending on the plastic crack opening of a circumferential through-wall crack and properly reflected the dependence on each parameter within the range over which the analytical expression was derived.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.41 no.3
• /
• pp.71-75
• /
• 2009

Cotton waste is usually used for cultivating agaric mushroom after outdoor fermentation for a few months. Electron beam was used to break down the polymer chaims of cotton waste for increasing low molecular weight soluble sugars, which may enhance the agaric mushroom cultivation. By increasing electron beam radiation, alpha cellulose content of the cotton waste was decreased while beta cellulose content and hot water solubles were increased. Electron beam radiation over 240 kGy on cotton waste caused significant increase of mushroom yield without lowering mushroom quality.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2018.05a
• /
• pp.277-277
• /
• 2018

Hwang (2015)은 불연속 지형을 지나는 천수 흐름의 해석에서 흐름률을 정확하게 계산하기 위하여 계단에 의한 흐름 저항이 지배적인 계단 전면과 그 영향이 비교적 덜한 계단의 윗부분을 구분하여 접근하는 새로운 기법을 제안하였으며, 모의 결과를 정확해 및 실험실 실험 결과와 비교하였다. 또한 전면 및 후면 계단을 지나는 댐 붕괴 흐름에 대한 실험(Kim et al., 2014)에 적용하여 기존 모형에 비해 새로운 기법에 의한 결과가 보다 우수함을 확인하였다(Hwang, 2016). Kim et al. (2015)은 좌안에 옹벽이 설치된 직선 수로에서 댐 붕괴 흐름에 대한 실험을 수행한 바 있다. 이 연구에서는 Kim et al. (2015)의 실험에 Hwang (2015)의 새로운 기법을 적용하였다. 댐 붕괴에 의한 주 흐름의 진행과 좌안에 직립인 옹벽에서 비교적 표고가 낮은 곳으로 물이 넘나드는 현상이 잘 재현됨을 확인하였다. 이 연구는 국토교통과학기술진흥원의 일부 지원(과제 번호: 14CCTI-C063749 그리고 18AWMP-C140010-01)에 의한 것이다.

• SUVANNABHUMI
• /
• v.7 no.1
• /
• pp.89-103
• /
• 2015

Over the last decade, the field of Southeast Asian Studies has been inundated with issues of its "territory" (or the definition of what comprises Southeast Asia), relevance and future. The methodology of approaching Southeast Asian Studies has also come under constant scrutiny providing much fodder for debate. One significant suggestion was that the field of Southeast Asian Studies should "break out of the comfort zone" (Van Schendel, Bijdragen, 2012:168(4)). This paper will explore some of the ways of approaching Southeast Asian Studies beyond that comfort zone by examining other/alternative units of studying Southeast Asia in place of the traditional (or statist) perspectives that tend to confine the field within the scope of the national/nation-state boundaries. The paper will also provide some personal observations of the author on the current state and limitations to teaching and researching Southeast Asian Studies in the region.