• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.786-789
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• 2005

The proper parameters in a twin roll strip casting are important to obtain the stabilization of the Mg sheet. What is examined in this paper is the quantitative relationships of the important control parameters such as the roll speed, height of pool region, outlet size of nozzle, solidification profile and the final point of solidification in a twin roll strip casting Unsteady conservation equations were used for transport phenomena in the pool region of a twin roll strip casting in order to predict a velocity, temperature distributions of fields and a solidification process of molten magnesium. The energy equation of cooling roll Is solved simultaneously with the conservation equations of molten magnesium In order to consider the heat transfer through the cooling roil. The finite difference method (2-D) and the finite element method (2-D) are used in the analysis of pool region and cooling roil to reduce computing time and to improve the accuracy of calculation respectively.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.1
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• pp.83-92
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• 2000

Sound intensity method is well known as a visualization technique of sound field or sound propagation in noise control. Sound intensity or energy flux is a vector quantity which describes the amount and the direction of net flow of acoustic energy at a given position. Especially two dimensional sound intensity method is very useful in evaluating periodic characteristics and acoustic propagation mode of noise source. In this paper, we have studied the noise source Identification, acoustic sound field analysis, and characteristics of noise source of rotary compressor and scroll compressor for air conditioner using complex sound intensity method. Also we proposed a now method of time domain analysis which is used in evaluating of position of noise source in rotary and scroll compressor in this paper This paper presents the advantage, simplicity and economical efficiency of this method by analysing the characteristics of noise source with two dimensional complex sound intensity simultaneously.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.3
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• pp.347-355
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• 2001

A heat transfer analysis in a ventilation chamber of Plasma Display Panel(PDP) has been conducted. The process requirement is to precisely follow prescribed temperature trajectory while maintaining temperature uniformity for each panel. Firstly, experiment in a test chamber has been carried out and the results are compared with the unsteady 3D numerical data. Reasonable agreement was found, which suggested that the employed numerical model had its credibility in actual PDP ventilation processes. On this ground, a tact-type heating/cooling system was analyzed. The panel temperature in the 40$^{\circ}C$ tact-type system was more uniform than that in the 80$^{\circ}C$ one. For improving the uniformity of panel temperature, relocation of ventilation head to the rear part and inlet flow control are required. Comparison of full simulation of a cart and simplified simulation of one panel indicates the optimized panel pitch can also be predicted.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup1
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• pp.159-164
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• 2001

Reduction cranioplasty is one of the treatment modality among many treatment options for macrocephaly with hydrocephalus. The most previous techniques of reduction cranioplasty have some disadvantages such as difficult airway maintenance, pressure sore due to modified prone position, severe venous infarct due to obstruction of venous blood flow and large amount of bleeding from the dissection of superior sagittal sinus to obtain bone fragment needed. A 28-month-old girl had extreme macrocephaly. She couldn't control head rotation and keep sitting position. The operation was performed at supine position with adequate exposure of entire calvarium and the hinge was made in occipital bone fragment that covered posterior part of superior sagittal sinus. Bleeding volume and the other complications were decreased and acceptable reduction was achieved with this method.

• Annual Conference of KIPS
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• 2014.04a
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• pp.12-14
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• 2014

하드웨어가 해저드(hazard) 검출을 지원하지 않는 멀티이슈 VLIW 프로세서의 성능을 높이기 위해서는 컴파일러가 명령어 의존성과 하드웨어 자원의 제약을 지키는 범위 안에서 최대한 명령어수준 병렬성(ILP)을 활용하는 것이 중요하다. 기본 블록(basic block) 스케쥴링은 Branch 등 제어 흐름(control flow)의 경계를 넘어선 스케쥴링을 행하지 않아 그 효과가 제한적이다. 소프트웨어 파이프라이닝(software pipelining)은 루프(loop)의 경계를 허물어 여러반본(iteration)의 명령어가 동시에 수행되도록 하는 것으로 모듈로 스케쥴링(modulo scheduling)은 그 중에 한 범주의 스케쥴링 기법들을 일컫는다. 본 연구에서는 그 중 한가지인 스윙 모듈로 스케쥴러(swing modulo scheduler)[1]를 구현하여 그 효과를 알아보고자 한다.

• The Journal of Industrial Distribution & Business
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• v.9 no.1
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• pp.25-38
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• 2018

Purpose - The purpose of this study is to empirically investigate the impact of donor's fiscal status on aid decisions before and after the 2008 global financial crisis. The effects on aid can change depending on the donor country's fiscal status and the period of financial crisis. Research design, data, and methodology - A fixed effect regression and dynamic panel GMM is conducted using a comprehensive dataset combining 31 donor and 167 recipient countries during 1996-2015. The key explanatory variable is central government debt-to-GDP ratio of donor country. Recipient countries' GNI per capita, population, governance indicators, and bilateral trade-to-GDP ratio between donor and recipient countries are included as control variables. Results - We can confirm the relationship between donor country's fiscal status and aid flow. The cyclical component of government debt is found to have a negative impact on grant decisions particularly after the 2008 global financial crisis. This effect becomes larger in the countries with high government debt-to-GDP ratio. ODA decisions from the countries with low financial constraint do not significantly affected by the recipient countries' factors such as GNI, population, and governance indicator. Conclusions - Based on the empirical results of this study, the source of aid should be diversified by incorporating private sector and innovative financing sources.

• Journal of International Academy of Physical Therapy Research
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• v.9 no.4
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• pp.1663-1668
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• 2018

This study was conducted to examine the effects of Evjenth-Hamberg stretching of the sternocleidomastoid, upper trapezius, and pectoralis major on the lung function of adults with forward neck posture. The subjects were 20 adult students in P university located in Pohang, Korea, whose degree of head forward displacement measured according to NEW YORK state posture test was mild. The subjects were randomly and equally assigned to the Evjenth-Hamberg Stretching group (EHSG, n=10) and the control group (CG, n=10). Their forced vital capacity (FVC), slow vital capacity (SVC), and maximal voluntary ventilation (MVV) were measured before and after the experiment. In within-group comparison, only the EHSG experienced statistically significant improvement in FVC, forced expiratory volume in the first second (FEV1), and peak expiratory flow (PEE) after the experiment, compared to before the experiment (.05

• Journal of Aerospace System Engineering
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• v.13 no.5
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• pp.16-23
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• 2019

This paper describes the design and analysis of a periscope imaging system installed at the engine test facility in the Agency for Defense Development. The periscope system is a cylinder-shaped image observation system installed at the rear of the engine and at the top of the diffuser. The periscope system has high risk of breaking because it is directly affected by high temperature (2300 K) and products of combustion. Thus, we used 1D heat transfer calculation, and 2D and 3D CFD analysis to confirm the heat flux and temperature distribution. Also, the cooling performance was verified. In the current design, using the periscope system, we can see flame shapes, control of the nozzle, and stability of the exhaust flow visually.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.125-128
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• 2008

As a interstage of the 30tonf level LOx/kerosene liquid rocket engine development, turbopump-gas generator open-loop coupled tests are performed. Test schematic and test results of open-loop coupled tests are presented. In engine system operation environment simulating combustion chamber by flow control orifice, chill-down procedure, startup characteristics, nominal operability of turbopump+gas generator open-loop coupled Test Plant are confirmed The results of open-loop coupled test were used for the preparation on turbopump+gas generator closed-loop test.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.310-313
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• 2008

Magnetohydrodynamics (MHD) devices have received considerable attention in recent years as a means to either improve the propulsive characteristics of hypersonic cruise missiles or as a means to generate power at low cost in drag and weight aboard scramjet powered vehicles. Based on more complete physical models than previously used, it is here argued that the use of MHD is not valuable in improving the performance of hypersonic propulsion systems through prevention of boundary layer separation or power bypass. This is due to the inevitable high amount of Joule heating accompanying MHD flow control having considerable undesired adverse effects on the engine performance. On the other hand, preliminary estimates indicate that MHD is likely to succeed in generating high amounts of power with little additional drag to feed megawatt-class energy weapons on-board scramjet engines.