• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2000.04a
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• pp.33-33
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• 2000

고온의 연소가스로부터 노즐 표면을 보호하기 위하여 슬롯을 통하여 냉각 유체를 분사하는 슬롯 막냉각에 대하여 연구하였다. 냉각효율 및 열전달 특성은 주유동과 2차 유동의 분사율에 따라 크게 달라지며, 형상변화 및 유동가속에 의해서도 냉각 효과의 변화를 가져오게 된다. 따라서 본 연구에서는 실험을 통하여 면적비가 16:1인 축소노즐에서 압축성 효과를 배제할 수 있는 유동속도 범위 내에서 분사율 변화(0.5 $\leq$ M $\leq$ 3.0)에 따른 슬롯 막냉각 열전달 특성을 고찰하고, 평판 슬롯 막냉각 경험식의 결과와 비교하였으며, 수치해석을 통하여 축소노즐과 원형관에서의 냉각효율 및 열전달 특성을 비교함으로서 이를 검증하였다. 축소노즐에서의 슬롯 막냉각 열전달 특성은 단열벽면조건을 형성하여 노즐 표면을 따라 설치된 열전대를 이용하여 측정하였다. 그 결과 상대적으로 낮은 분사율(M=0.5, 1.0)에서 분사율 증가에 따른 냉각효율의 증가가 크게 나타났으며, 분사율이 높아짐(M $\geq$ 2.0)에 따라 냉각효율의 증가폭이 점점 감소하고, 일정 분사율 이상에서는 냉각 효율의 증가가 크게 둔화되었다. 분사율이 낮을 경우 평판 슬롯 막냉각 경험식으로 주어진 결과보다 상류에서는 높으나 하류로 진행하면 비슷한 냉각효율을 보였고, 분사율이 높은 경우 평판보다 전 범위에서 약간 높은 냉각효율을 나타냈다. 수치해석 결과에서는 분사율이 낮을 경우 축소노즐의 냉각효율이 원형관에서의 냉각효율 보다 낮거나 비슷하게 나타났으며, 분사율이 높아짐에 따라 축소노즐에서의 냉각효율이 오히려 높아지는 것으로 나타났다.타내었다. 액체 제트의 속도는 처음에는 일정하게 유지되다가 운동량을 보존하기 위해 가스로부터 운동량을 받아 점차 가속되어지는 것으로 나타났다.본 규격은 키, 총장, 어깨길이, 등길이, 머리길이, 머리둘레, 진동둘레, 목둘레, 가슴둘레, 허리둘레, 배둘레, 엉덩이둘레, 앞품, 뒤품, drop치를 포함하고 있고, 각 규격에서 호칭간 치수 간격도 함께 제시하고 있다. 본 연구 결과에서 보듯, 현행 8규격의 무진복의 각 호칭간 적정 허용범위를 고려해 합리적인 치수체계를 정립한다면 치수에 대한 적합도가 상당히 증가할 뿐 아니라 생산비용도 상당히 감축할 것으로 생각된다.나타났다. 4) 호감적 서비스능력 차원에서 세 독립변수간에 유의한 3원 상호작용이 존재하는 것으로 나타나( $F_{2,228}$=15.62, P<.001) 20대에 적합한 의복 착용시( $F_{2,228}$=3.98, P<.05)와 60대에 적합한 의복 착용시( $F_{2,228}$=16.55, P<.001) 점포유형과 격식차림간에는 유의한 상호작용이 존재하는 것으로 나타났다. 5) 호감을 구성하는 세 요인들이 구매의도에 미치는 영향을 조사한 결과 호감적 인상차원은 29%(P<.001), 호감적 서비스능력차원은 6%(P<.001)의 구매의도를 설명해 주는 것으로 나타났다. 본 연구결과 노년 소비자에게 호감을 주는 판매원의 외모는 구매의도에 영향을 주어 실버의류산업의 이익증대와 밀접한 연관을 갖는 서비스품질의 중요한 요인으로 밝혀졌다.중요한 요인으로 밝혀졌다.로운 단백질 EPSPS가 다른 여러 식물에 이미 존재하고 있는 단백질로서 우리가 이미 이러

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.4
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• pp.55-61
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• 2010

This paper is concerned with an experimental research to random vibration control caused by external loads specially in bridges which tend to be structurally flexible. Experimenting on a reduced structure modelled on Seohae Grand Bridge, we inflicted a reduced form of El-centro wave on the model structure to a proper proportion. On the center of its middle span, we placed a shear type MR damper which was to control its vibration and also acquire its structural responses such as displacement and acceleration at the same site. The experiments concerning controlling vibration were performed according to a variety of theories including un-control, passive on/off control, and Lyapunov stability theory. Its control performance was evaluated in terms of the peak absolute displacements, the peak absolute accelerations and the total power required to control the bridge which differ from each different experiment method. Among all the methods applied in this paper, case of Lyapunov control method turned out to be the most effective to reduces of displacement and acceleration. Also, this method could to decrease consuming of external power for vibration control. Finally, it was noteworthy that Lyapunov control method was specially effective in the vibration control employing a semi-active damper such MR damper.

• Journal of The Korean Association For Science Education
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• v.22 no.3
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• pp.422-431
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• 2002

Because of the gap between the cognitive levels of the students and the curricular materials for the students to understand, the secondary school students feel science difficult and they get to avoid science as they go up to the higher grade. So it is absolutely needed to take the active measures to improve the cognitive development of the students through some special programs stimulating their cognitive process. This study investigated the effects of thinking science activity program devised for cognitive acceleration of the students. After implementing thinking science program to 181 7th grade students, the effectiveness of this program was examined through the analysis of covariance of both experimental and control groups. The result of the study showed that the cognitive level of the students in experiment group dealt with thinking science program was more accelerated than that of the students in control group who were just taught regular science curriculum. Especially, the effect was clear to the students in stages 1 and 2B. It was also found that the percentage of the students who promoted from concrete operational stage to formal operational stage was higher in experimental group than in control group. The results of the study implied that cognitive acceleration of the students might be possible through the specially designed materials such as thinking science program.

• Journal of Convergence for Information Technology
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• v.10 no.2
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• pp.184-192
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• 2020

This study presents a gait analysis method (including time series analysis) using a smart insole as an objective and quantitative evaluating method after lumbar scoliosis surgery. The participant is a degenerative lumbar scoliosis patient. She took 3-min-gait-test four times(before and 8, 16, and 204-days after surgery) and 6-min-gait-test once(204-days after surgery) with smart-insoles in her shoes. Each insole has 8-pressure sensors, an accelerometer, and a gyroscope. The measured values were used to compare the characteristics of gait before and after surgery. The analysis showed that all of the patient's gait parameters improved after surgery. And after 6 months, the gait was more stable. However, after long walk, the swing duration of one leg was slightly shorter than that of the other again. It was a preclinical problem that could not be found in the visual examination by the practitioner. With this analysis method we could evaluate the improvement of patient quantitatively and objectively. And we could find a preclinical problem. This analysis method will lead to the studies that define and distinguish gait patterns of certain diseases, helping to determine appropriate treatments.

• Journal of Digital Convergence
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• v.15 no.4
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• pp.529-536
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• 2017

The purpose of this study is to examine the immediate effects of spiral taping applied to an affected leg on gait ability in stroke patients. Forty two stroke patients were divided into a spiral taping group (n=21) and a quadriceps femoris group (n=21), and each taping method was applied. Spatiotemporal Gait Parameters (Cadence, speed, gait cycle duration, stance phase duration, double support duration) were measured using the 10-meter walk test, the dynamic gait index (DGI) and an accelerometer for both groups. Both groups showed a significant increase in a 10-minute walk, the DGI, cadence, speed before and after the intervention, whereas no significant difference was detected in stance phase duration, gait cycle duration and double support duration on the affected side in all groups. All groups revealed no significant difference in variation. It has been found that the two taping methods augment gait ability in patients with stroke. This study suggests that spiral taping can be an easily applicable method at home.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.1
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• pp.85-94
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• 2011

This paper is concerned to constitute a semi-active realtime feedback vibration control system and evaluate it through experiments in order to control in realtime the vibration externally generated, specially on the bridges which is structurally flexible. For the experiment of vibration control, we built a model bridge structure of Seohae Grand Bridge in a 1/200 reduced form and inflicted El-centro wave on the model structure also in a reduced force considering the lab condition. The externally excited vibration was to be controled by placing a shear type MR damper vertically on the center of bridge span, and the response (displacement and acceleration) of structure was to be acquired by placing LVDT and Accelerometer at the same time. As for the experiment concerning controlling vibration, a realtime feedback vibration control experiments were performed under each different condition largely such as un-control, passive on/off control, Lyapunov stability theory control, and Clipped-optimal control. Its control performance under different condition was quantitatively evaluated in terms of the peak absolute displacements, the peak absolute accelerations and the power required for control on the center of span. The results of experiments proved that the Lyapunov control and clipped-iptimal control were effective to decrease the displacement and acceleration of the structure, and also to decrease the power consumption to a great extent. Finally, the semi-active realtime feedback vibration control system constituted in this research was proven to be an effective way to control and manage the vibration generated on bridge structure.

• Journal of the Korean Institute of Gas
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• v.13 no.5
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• pp.1-6
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• 2009

This paper presents the fuel consumption effects of LPG vehicle depending on the atmospheric temperature, LP gas leakage of vaporizer, viscosity of engine oil and engine load conditions. The fuel consumption test results show that when the temperature of engine temperature rises, the fuel consumption efficiency increases in general. The fuel consumption efficiency for an atmosphere temperature of $24.2^{\circ}C$ is 13.6% high compared to that of $1^{\circ}C$. No leak vaporizer on fuel consumption efficiency is 5.3% high compared to that of the LP gas leak vaporizer. The fuel economy of new engine oils is just 1.1% high compared to that of used oils with a LPG vehicle mileage of 9,500km. This is not an influential factor compared with an atmospheric temperature and a LP gas leakage. The more important factors on the fuel consumption efficiency are driving conditions such as a rapid braking, abrupt start and fast acceleration. The test results indicate that the normal start is 32.3% high compared to that of an abrupt start and the fast acceleration is 10.8% high compared with that of an abrupt start. And the fuel consumption efficiency for a rapid braking is 18.3% higher than that of an abrupt start. These indicate that the driving condition is very important to reduce the fuel consumption rate.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.4 s.50
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• pp.77-84
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• 2006

Recently, as large structures such as high-rise building and long span bridge become lighter and more flexible, the necessity of structural control for reducing excessive dynamic response due to seismic excitation is increased. In this study, a semi-active base isolation system using Magneto-Sensitive (MS) rubbers is proposed to effectively protect structures against earthquakes. MS Rubber is a class of smart controllable materials whose mechanical properties change instantly by the application of a magnetic field. To demonstrate the performance of this device, the MS Rubber isolation system is compared to Lead-Rubber Bearing (LRB) isolation systems and judged based on computed responses to several historical earthquakes. The MS Rubber isolation system is shown to achieve notable decreases in base drifts over comparable passive systems with no accompanying increase in base shears or in accelerations imparted to the superstructure. The proposed MS Rubber system is shown to perform better than the passive isolation system.

• Journal of Korea Multimedia Society
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• v.17 no.1
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• pp.77-93
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• 2014

Kinetic typography has been suggested to express emotions in computer-mediated communication (CMC) by empowering static texts with dynamic attributes, where conversations occur primarily in text-based forms. In this work, we investigate whether pre-defined kinetic typography effects are capable of delivering emotions, and further, which specific attributes of kinetic typography arouse such emotions. The results show that emotional response of users were corresponding to the emotions intended by experts, indicating that pre-defined kinetic typography is an applicable way to express emotions consistently in CMC. Also, results demonstrate some key attributes that derive certain levels of mood and energy respectively. Energy level turned out to be affected by the font size, transparency, direction of movement, amount of movement, velocity, and acceleration of the text, while mood level was influenced by the transparency, direction of movement, regularity in movement, and speed of the text.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.197-202
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• 2005

The electromagnetic signals associated with the seismic activity in the south-east offshore of Kii peninsula, Japan, were clearly recorded at the MT sites in Jeju island, Korea. In this research, we have identified the co-seismic electromagnetic signals associated with the seismic activity and have analyzed the characteristics of significant electromagnetic variations. The analysis of phase velocity, power spectral density, MT impedance and polarization direction shows that the significant earthquake signals have the frequency band of about 0.05 to 0.5 Hz and that the sources of electromagnetic field are local effects of passing seismic waves. The simple approximation using electrokinetic effect successfully explains the co-seismic EM signals coincides with measured data but cannot explain the localities of electromagnetic variations.