• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.5 s.248
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• pp.465-471
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• 2006

Controlled auto-ignition(CAI) combustion, offers the potential to improve fuel economy and reduce emission simultaneously. In this study, CAI-combustion was achieved in a single cylinder gasoline DI engine with modified camshafts in order to restrict the gas exchange process. We investigated the effects of air-fuel ratio, residual EGR rate and injection timing such as early injection and late injection on the attainable CAI combustion region. The effect of injection timings on combustion characteristic such as start of combustion, combustion duration and heat release rate was also investigated. From the result early injection causes the mixture to ignite earlier and burn more quickly due to the exothermic reaction during the recompression and gives rise to good mixing of the fuel/air. On the other hand, late injection extended the operation region more than early injection but the emissions of HC and NOx were more or less increased than early injection.

• Korean Journal of Applied Biomechanics
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• v.31 no.3
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• pp.168-175
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• 2021

Objective: To investigate the static and dynamic analysis of ankle joint complex between subjects with chronic ankle instability (CAI) and healthy controls. Method: A total of 38 subjects and CAI group (N=19) and healthy control (N=19) participated in this first study. Variables that were measured in this study were as follows: 1) Subtalar joint axis inclination and deviation 2) Rearfoot angle 3) Navicular drop test 4) Heel alignment view in alignment analysis. Intra Correlation Coefficient (ICC) is used for reliability. A secondary 17 subjects are recruited including 9 of CAI and healthy for gait analysis between group. Lower extremity sagittal, frontal, and transverse kinematics were measured. All data were analyzed to ensemble curve analysis. Results: 1) There were statistically significant differences in standing rearfoot, navicular drop, heel alignment view, subtalar joint (STJ) inclination and deviation. 2) Only in sagittal, meaningful difference is showed during walking in gait analysis. Conclusion: Morphological problem can affect ankle sprain in aspect of structure with no relation to compensation of neuromuscular.

• Korean Journal of Applied Biomechanics
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• v.33 no.3
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• pp.94-100
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• 2023

Objective: Few studies have investigated alterations of ground reaction force (GRF) in individuals with chronic ankle instability (CAI) compared with lateral ankle sprain (LAS) copers and healthy controls during walking. This study aimed to investigate differences in GRF variables among the CAI, LAS coper, and control groups. Method: Eighteen individuals with CAI, 18 LAS copers, and 18 healthy controls were recruited for this study. All participants walked on 8-m walkway with a force plate three times. GRF data during stance phase were extracted and analyzed. The analysis of variance and ensemble curve analysis were used for statistical analyses of discrete points and time-series data respectively. Results: The CAI group showed a greater loading rate (LR) and a shorter time to impact peak force than the other groups, as well as decreased vGRF from 56% to 65% in the stance phase than the control group. No significant differences were noted in the other variables. Conclusion: Based on these findings, individuals with CAI should enhance their ability to create propulsion during the push-off phase and spend more time absorbing GRF to decrease the LR, which is considered one of risk factors for overuse injury and ankle osteoarthritis.

• Composites Research
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• v.22 no.6
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• pp.18-22
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• 2009

In this paper, we examined impact force and impact behavior through low velocity impact tests of composite laminates. And through c-scan as nondestructive inspection, explored the damaged area being difficult to examine with the visual inspection. Through CAI tests, we also measured the compression strength of composite laminates subjected to low velocity impact. To examine the characteristics of impact behavior measured from low velocity impact test, nondestructive inspection, and CAI test, the simulated data are generated from the test data using Monte-Carlo simulation, then represented it by probability distribution. The testing results using visible stochastic distribution were examined and compared.

• The Mathematical Education
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• v.24 no.2
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• pp.35-47
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• 1986

As computer is diffused in society widely, it is desired that we investigate on computer uses in school education. In this paper, Possibility of Micro computer uses in mathematics education is investigated. Educational computing is classified roughly three categories they are CAI CMI and Computer iteracy education. CAI is discussed at this place. Firstly, programs of mathematics educational computing is introduced and they are classified into Practicing, Tutoring, Simulating, Gaming, Demonstration, Informing. Next, the problems that we must notice in mathematics educational computing are indicated. They are computer language, development of soft ware, effectiveness of CAI etc...

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.468-472
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• 1989

In this paper a Korean authoring system is designed to write a CAI courseware in Hangul/English by an author who is a nonprogrammer. It saves nock time in authoring a courseware and maintains high level transplantity among CAI systems. By interfacing ah expert graphic utility, image information can be processed more easily and efficiently. Programming control of the flow of CAI courseware can be ramification and individual learning possible, fitting various demands of learners and learning and learning ability.

• Journal of the Korean Chemical Society
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• v.49 no.6
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• pp.575-583
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• 2005

• Journal of the Korean Home Economics Association
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• v.35 no.1
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• pp.221-236
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• 1997

Koreans who put a high value on confucian ethics traditionally have considered sex problems as taboo. Being faced with western liberal and hedonic culture that comes with waves of industrialization our younger generation who has grown in cultural backgrounds of confucianism has had mental confusion. Due to higher standards of living physical growth has quickened but mental growth has not reached there instead. Because of lureand trouble which come from this problem related with sex this is considered as a social problem. In this research through judgement which the most effective way that can solve adolescence sex problems is systematic sex education teaching method for desirable sex education is presented asfollowing First some supplement and desirable direction of sex education were proposed through the analysis of eight currently using home economics texbooks. A lesson plan was proposed using CAI program which was developed by authors with assistance of professional computer programmers. The CAI program includes following curriculum contents: 1concepts of sex This study ultimately aimed to let students develop desirable attitude and perspective on value regarding adolescence and sex, For this goal of research another lesson plan was proposed fostering classroom group discussion.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.12
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• pp.109-118
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• 1999

The objective of this research is to develop an effective inspection planning strategy for sculpture surfaces in OMM(On-Machine Measurement) process. As a first step, effective measuring point locations are determined to obtain optimum results for given sampling numbers. Two measuring point selection methods are suggested in this study based on newly proposed CAD/CAM/CAI integration concept: (1) by the prediction of cutting errors, (2) by considering cutter contact points to avoid the measurement errors caused by cusps. As a next step, the TSP(Traveling Salesman Problem)algorithm is applied to minimize the probe moving distance. Appropriate simulations and experiments are performed to verify the proposed inspection planning strategy in this study, and the results are analyzed.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.4
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• pp.447-456
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• 1996

본 논문은 선박 기관사의 실무 능력 평가를 위한 CAI 시스템의 설계와 구현에 관한 것이다. 지금까지 실무 기관사들을 위한 평가 시험은 주로 필답 시험과 구두 시험에 의존해 왔지만, 컴퓨터를 이용할 CAI 시스템을 사용함으로써 평가에 걸리는 시간을 단축할 뿐만 아니라 효율적인 평가를 할 수 있다. 시스템의 구성은 영역 지식, 질문, 예제 등으로 구성되어 있으며 13 관련 분야에 바탕을 두고 있다. 이 시스템의 사용자는 교사, 실습생, 학생, 선박관련 전문가들이 될 수 있다. 또한 이 시스템을 Client/server 환경으로 확장하기 위하여 Oracle 7.3과 PowerBuilder 5.0을 이용한 실험적인 환경을 설계하고 대표적인 Client page를 보여주고 있다.