• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 추계학술대회
• /
• pp.356-361
• /
• 2003

The objective of this study is a qualitative comparison between line-integrated OH chemiluminescence ($OH{\ast}$) image and its Abel inversion image at different phase of the oscillating pressure field. PIV(Particle Image Velocimetry) measurements were conducted under non-reacting conditions to see the global flow structure. Also NOx emission was measured to investigate the effect of fuel-air premixing on combustion instability and emission characteristics. Experiments were carried out in an atmospheric pressure, laboratory-scale dump combustor operating on natural gas. Combustion instabilities in present study exhibited a longitudinal mode with a dominant frequency of ${\sim}341.8$ Hz, which corresponded to a quarter wave mode of combustor. Heat release and pressure waves were in-phase when instability occurred. Results gave an insight about the location where the strong coherence of pressure and heat release existed. Also an additional information on active control to suppress the combustion instabilities was obtained. For lean premixed combustion, strong correlation between $OH{\ast}$ and NOx emissions was expected largely due to the exponential dependence of thermal NOx mechanism on flame temperature.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2006년도 춘계학술대회 논문집
• /
• pp.439-440
• /
• 2006

This research proposes a novel method of shape display to present 3-dimensional objects. Shape displays allow us to feel the actual volume of the object, unlike conventional 2D visual displays of 3D objects. The proposed method employs a wire frame structure to present 3D objects. The wire frame is composed of small units driven by shape memory alloy(SMA) actuators. The drive unit is analogous to the agonist-antagonist system of animal musculoskeletal systems, where the SMA actuators serve as agonist and antagonist muscles. The force in the SMA actuator is controlled by electrical current. The drive unit is equipped with the locking mechanism so that it can sustain the external force exerted by the user as well as the own weight of the wire frame structure. By controlling the current into the SMA actuator and locking mechanism, we call control the angle of the drive unit. A chain of drive units enables presentation of 2 dimensional objects. 3 dimensional presentations are possible by collecting the chains of drive units.

• 대한가정학회지
• /
• 제12권34호
• /
• pp.679-697
• /
• 1974

I. Preface A. Establishment. There are many psycological and physiological difficulties that students have made practical application to a building site of 600 pyung and a structure of 65 pyung each sixteen students in the Home Management House, but there exists problem in students apprentice and management of professors. B. Purpose of study This research aim to seek a high degree of efficiency approach in investigating, studying and analyzing factors of the problem in Home Management which have been faced in women colleges in seoul. C. Content of study. This study is aim at finding out the problems including facilites, system, guiding principle, working bottleneck and administrative problem in making practical application of Home Management. II. A plan and method of study A. This subject of statiscal research is 616 women students in senior year from september 27 1970 to October 31 1974. The rate of collection of questionnaire is 100 percent. B. The Method of study is devised through refering documents, interview with students, questionnaire and observation. III. Result of study Of the total of 29 university in seoul, 24 Universities have its Course of Home Economic among which only 12 have Home Management for making practical application. Home Management House for making practical application is located mainly in campus but some of them exceptimally are in outside university. Students practice mainly at civilzed resident, apartment, bangalow so forth, and demention of which occupies approxiamtely 50-600 pyung (land) and 20-70 pyung (Building). A member with 4 or 20 students make practical application from 10 days to 3 months. A member consists of students and assistant teacher, and practice site classifies into living school for Professors living, and another school for Professors and assistant teachers. Answer to a questionnaire. 616 students answer to a questionnaire. 49 Perfect of 616 students like to have a member with 12 students like to have a member with 12 students, 38 percent student a member with 16 students. About the period of making practical About the period of making practical application, 76 percent students like to have two or three week period. 19 percent students think it a short period and 4 percent students think it a long period. There is none who thinks 25 day period day period to be short. About making practical application, 66 percent of 616 students feel uneasy, 40 percent students feel lack of sleep and tired. Students take a pleasure in having a conversation with their friends, inviting their mother, having dinner-party and birthday party. 77 percent students want to invite their father and 67 percent students want to invite their boy-friends. It is hard to have a good personal relation about the great the result of practice, students acknowledge themselves that they have learned about Cautiousness and they are sure of good Home Manager. There are 9 difficult problems during the period. IV. Summary discussion a. Many problems come from having a number of students. b. Students feel tired with their practice if over three weeks. No Matter how good a plan is, it useless if students can't adapt themselves to it. Suggestions 1) it is good to have a member with 5 or 6 students, and it is suitable to have two or three week period, and to have an area of 20 or 30 pyung. 2) it's proposed a profess or to live together in making practical application of Home Management 3) it is proposed a professor to have a sure T.O. and to be treated better.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
• /
• pp.1285-1288
• /
• 1997

The basic technology of virtual reality can be described as the cognition of the condition change in virtual world by stimulating the visual, auditory, kinesthetic and tactile sensation. Among these, the kinesthetic and tactile sensation is one of the most important things to recognize the interaction. In this paper, it is addressed the haptic device which help the human feel the sense of the operator, and is designed in modular type to expand for five fingers later. the haptic device is driven by tendon and ultrasonic motors located in the wrist part. Each joint is actuated by coupled tendons and adopts more actrator by one than the number of the joints, called 'N+1 type'. The haptic device adopts metamorphic 4-bar linkage structure and the length of linkages, shape and the location of joint displacement sensor are optimized through the analysis.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2004년도 춘계학술대회논문집
• /
• pp.699-704
• /
• 2004

As being inconvenient to apply reinforced concrete structure to high-rise buildings, it is applied steel structured system. Therefore light-weight wall systems are applied as partition wall to reduce the self-load of the building. But, the required performances of a light-weight wall are not evaluated systematically. As a field survey result, partition walls of house-to-house were not showed their respected performances, so the dwellers are feel so worse the quality of the whole building. In steel-structured high-rise buildings especially, occupant's dissatisfaction concerned indoor noise was high because curtain wall systems having a high air-tight performance isolate the outdoor noise making masking effect. Therefore wall systems which have high performances of sound insulation and air-tightness are required in high-rise buildings. As a result, a new drywall system was presented and the performance was verified with field test.

• 한국안전학회지
• /
• 제24권3호
• /
• pp.19-24
• /
• 2009

Currently the technique of composite material field is developed day by day. The many kinds industrial facility and life articles are coming to make with the composite material. But still the engineering works field the building and the bridge uses the material which is old era and is making. To here there is a various problem but the biggest problem the theory of the composite material is complicated too and means that the application is been delayed about constructive structure. When the composite material is used widely from constructive field, too with difficult theory in technical expert and easily with the research for the experiment data accumulation is necessary. The tensile and fatigue test of the carbon/epoxy which is a high-class composite material led from the present paper consequently and the change of the intensity coefficient which follows in repeated load researched.

• 통상정보연구
• /
• 제12권4호
• /
• pp.127-149
• /
• 2010

It is well known that FTA increases consumer welfare. However, it is difficult to analyze consumer welfare effects of FTA for item by item because of the difficulty in data collection. In this respect, this study aims at analyzing the types of increasing consumer welfares with item by item. According to the result of the study, there are five types of consumer welfare increased by FTA, and the items are like below: banana, kiwi, octopus, wine, and etc. However, it is hard for consumer to feel effects of FTA directly for several reasons. The problem of distribution structure of imported goods and, tariff reductions over long period are parts of the reasons to reduce the consumer wealfare effects. And the lack of consumer awareness about imported goods also reduces them. In order to promote FTA more efficiently, this study suggests that the government must improve the problems mentioned because consumer consent is essential element for further FTA promotion.

• 한국의류학회지
• /
• 제28권3_4호
• /
• pp.414-421
• /
• 2004

To reduce farmer's stress from solar radiation and ultraviolet radiation(UV), the sunshade hat with a large brim and special structure for ventilation was developed and tested with manikin heads outdoors at previous study(Kim and Choi, 2002). To evaluate the protection efficiency of the sunshade hat, human trial test was performed at outdoors. The results were as follows; Skin temperatures(7 sites), heart rate, temperature inside the hats, temperature and relative humidity inside clothing on the back in wearing developed sunshade hat were significantly lower than those in wearing the controlled hat. In subjective sensation, subjects answered to feel significantly hotter, more humid and more uncomfortable in wearing the controlled hat. But relative humidity inside the hats was significantly higher in wearing developed hat. In rectal temperature, there were no significant differences between two hats.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
• /
• pp.119-122
• /
• 2007

Dual auxiliary pulses are adopted in an AC PDP with an auxiliary electrode. The secondary auxiliary pulse of dual auxiliary pulses efficiently utilizes priming particles and contributes to improved luminous efficacy. A shorter time interval between the two auxiliary pulses resulted in better efficacy. The maximum luminous efficacy was approximately 12 lm/W according to measurement of the discharge in a Ne+20%Xe gas-mixture and green cells.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 B
• /
• pp.1348-1350
• /
• 2000

Zero-voltage and zero-current switched single-stage approach with high power factor is presented to reduce the switching losses and to achieve sinusoidal, unity power factor input currents. This single-stage approach, which combines a boost converter used as PFC with a half-bridge converter used as do to do conversion into one power stage, has a simple structure and low cost. At the same time, since the switches of the proposed converter are designed to be turned on at zero-voltage and off at zero-current, the switching losses could be reduced considerably. Detailed analysis and experimental results are presented on the proposed converter, which is operated at constant switching frequency and in discontinuous conduction mode.