• 전력전자학회논문지
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• 제18권4호
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• pp.403-411
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• 2013

This paper proposes an isolated bidirectional three-phase push-pull dc-dc converter for high power application such as eco-friendly vehicles, renewable energy systems, energy storage systems, and solid-state transformers. The proposed converter achieves ZVS turn-on of all switches and volume of passive components is small by an effect of three-phase interleaving. The proposed converter has identical switching pattern for both boost and buck mode, and therefore can provide seamless characteristic at the mode transition. A 3kW prototype of the proposed converter has been built and tested to verify the validity of the proposed operation.

• 한국식생활문화학회지
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• 제26권6호
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• pp.574-582
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• 2011

The aim of this study was to classify Korean consumers based on their food-related lifestyle type, and to investigate the relationship between sushi consumption and food-related lifestyle type. Self-reported questionnaires were completed by 300 Korean adults. The SPSS 18.0 program was used to analyze the samples. Data was analyzed by frequency, descriptive factor, reliability, cluster analysis, ANOVA, and chi-square test. A factor analysis extracted four factors comprising foodrelated lifestyle, which we named Health-seeking (factor 1), Taste-seeking (factor 2), Convenience-seeking (factor 3), and Economy-seeking (factor 4). According to a cluster analysis based on those four factors, consumers were classified into three clusters. Cluster 1 was the Taste and Health-seeking cluster, Cluster 2 was the Convenience-seeking cluster, and Cluster 3 was the Passive Eating Habits cluster. The results also indicated that the selection attributes of each cluster were significantly different in terms of perception, the global state of sushi, sushi preference, frequency, companions, place of sushi consumption, and preference for different sushi sub-ingredients. Based on these results, consumer characteristics in the sushi market are discussed.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2009년도 학술대회
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• pp.62-67
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• 2009

기존의 증강현실 기반 상호작용 기법은 상호작용 주체의 원활한 추적을 위해 마커 기반의 패들이나 데이터 글러브 등의 부가적인 입력장치에 의존하거나 제한적인 3차원 입력만을 허용하는 경우가 많았다. 본 논문에서는 대상 개체 주변 공간의 물리적 점유를 감지하여 사용자의 입력을 해석하는 비접촉식 수동형 공간 상호작용 기법을 제안한다. 제안된 방법은 깊이 카메라로 구성한 증강현실 환경에 가상의 공간 센서를 배치하여 사용자의 입력을 공간적으로 해석한다. 그 결과, 부가적인 입력장치의 착용이 필요하지 않으며, 입력 형태에 대한 제약을 최소화하고, 증강된 영상 내의 상호작용 객체 간에 정확한 거리감을 제시한다. 향후 이러한 기법은 미니어쳐 AR 시스템과 같은 동적 콘텐츠 전시 플랫폼의 인터페이스에 적용될 것으로 기대된다.

• 기본간호학회지
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• 제7권3호
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• pp.379-390
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• 2000

Euthanasia have received considerable attention recentely in medical literature, public discussion, and proposed state legislation. Almost all the discussion in this area has focused on the role of physicians. However, nurse may be in special position to understand the wishes of patients and to act on this understanding. Purpose of this study is to identity the meaning of euthanasia in terminal ill patients on the nurses' veiw. Forcused interveiw design was used to data collection The data were analyzed by semantic analysis, and analysis of the data resulted in identification of 14 categories representing the meaning of euthanasia. 1. The meaning of supported euthanasia is 'free of suffering', 'difficulty of economic status', 'right of patient and family', 'dignity of death', 'organ transplant', 'social legislation'. 2. The meaning of opposited euthanasia is 'artificial death', 'value of life', 'uncertainity', 'guilt feeling' 3. The meaning of care in terminalily ill patients is 'avoidance', 'powerlessness'. 'apathy'. 'passive attitude'. The policy debate about professional roles in action that end of lives of patients must be extended nurses. Nurses must take an active role in discussion and definition of acceptable practice at the end of life.

• Smart Structures and Systems
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• 제16권5호
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• pp.937-960
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• 2015

Tuned mass dampers (TMDs) have been a prevalent vibration control device for suppressing excessive vibration because of environmental loadings in contemporary tall buildings since the mid-1970s. A TMD must be tuned to the natural frequency of the primary structure to be effective. In practice, a TMD may be assembled in situ, simultaneously with the building construction. In such a situation, the respective dynamic properties of the TMD device and building cannot be identified to determine the tuning status of the TMD. For this purpose, a methodology was developed to obtain the parameters of the TMD and primary building on the basis of the eigenparameters of any two complex modes of the combined building-TMD system. The theory was derived in state-space to characterize the nonclassical damping feature of the system, and combined with a system identification technique to obtain the system eigenparameters using the acceleration measurements. The proposed procedure was first demonstrated using a numerical verification and then applied to real, experimental data of a large-scale building-TMD system. The results showed that the procedure is capable of identifying the respective parameters of the TMD and primary structure and is applicable in real implementations by using only the acceleration response measurements of the TMD and its located floor.

• Smart Structures and Systems
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• 제16권6호
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• pp.1003-1021
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• 2015

MR dampers have been proposed for the control of cable vibration of cable-stayed bridge in recent years due to their high performance and low energy consumption. However, the highly nonlinear feature of MR dampers makes them difficult to be designed with efficient semi-active control algorithms. Simulation study has previously been carried out on the cable-MR damper system using a semi-active control algorithm derived based on the universal design curve of dampers and a bilinear mechanical model of the MR damper. This paper aims to verify the effectiveness of the MR damper for mitigating cable vibration through a full-scale experimental test, using the same semi-active control strategy as in the simulation study. A long stay cable fabricated for a real bridge was set-up with the MR damper installed. The cable was excited under both free and forced vibrations. Different test scenarios were considered where the MR damper was tuned as passive damper with minimum or maximum input current, or the input current of the damper was changed according to the proposed semi-active control algorithm. The effectiveness of the MR damper for controlling the cable vibration was assessed through computing the damping ratio of the cable for free vibration and the root mean square value of acceleration of the cable for forced vibration.

• 한국대기환경학회지
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• 제19권4호
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• pp.397-414
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• 2003

The performance of one-particle stochastic Lagrangian models for passive tracer dispersion are evaluated against measurements in horizontally-homogeneous neutrally-stratified atmospheric surface layer. State-of-the-technology models as well as classical Langevin models, all in class of well mixed models are numerically implemented for inter-model comparison study. Model results (far-downstream asymptotic behavior and vertical profiles of the time averaged concentrations, concentration fluxes, and concentration fluctuations) are compared with the reported measurements. The results are: 1) the far-downstream asymptotic trends of all models except Reynolds model agree well with Garger and Zhukov's measurements. 2) profiles of the average concentrations and vertical concentration fluxes by all models except Reynolds model show good agreement with Raupach and Legg's experimental data. Reynolds model produces horizontal concentration flux profiles most close to measurements, yet all other models fail severely. 3) With temporally correlated emissions, one-particle models seems to simulate fairly the concentration fluctuations induced by plume meandering, when the statistical random noises are removed from the calculated concentration fluctuations. Analytical expression for the statistical random noise of one-particle model is presented. This study finds no indication that recent models of most delicate theoretical background are superior to the simple Langevin model in accuracy and numerical performance at well.

• 한국정밀공학회지
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• 제17권10호
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• pp.69-76
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• 2000

Lots of semi-active control devices have been developed in recent years because they have the best features of passive and active system. Especially, controllable magneto-rheological(MR) fluid devices have received significant attention in these area of research. The MR fluid is the material that reversibly changes from a free-flowing, linear viscous fluid to a semisolid with a controllable yield strength in milliseconds when exposed to a magnetic field. If the magnetic field is induced by moving a permanent magnet instead of applying current to a solenoid, it is possible to design a MR damper consuming low power because the power consumption is reduced at steady state. This paper proposes valve mode MR damper using permanent magnetic circuit that has wide range of operation with low power consumption, a design parameter is adopted. The magnetic circuit, material of choke and choke type are selected experimentally with the design parameter. The behaviors of the damper are examined and torque tracking control using PID feedback controller is performed for step, ramp and sinusoidal trajectiories.

• 한국정밀공학회지
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• 제23권3호
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• pp.125-131
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• 2006

Recently air pollution has become an important issue. So, as tile number of vehicles increases, the noise pollution has become one of the most serious social issues nowadays. It is a muffler, which is one of the vehicle components. that has the hugest impact on the noise from the vehicle. And it also has a direct influence on the engine performance. So lately the research is proceeding on tile semi-active muffler which can control the back pressure variably by setting up the exhaust variable valve in the baffle to improve its internal structure. The inner parts of muffler which consist of a baffle, pipes and etc. appear to have the complicated turbulence phenomena by the pulsational wave of an unsteady state in the engine and by the structural characteristics of the inner parts. To analyze these phenomena, it is required to have an analysis of its constant quantity and quality. Therefore this study is to analyze with PIV measurement which can analyze the time and space variables, not with the point measurement method like former multi-point anemometer. It is to suggest proper design variables which need to make internal structure of the muffler improve though comparison between the passive type muffler and the semi-active muffler by fabricating a muffler which can be visualized.

• Corrosion Science and Technology
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• 제9권3호
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• pp.129-136
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• 2010

The corrosion behaviors of 316L stainless steel were investigated in simulated anodic and cathodic environments for proton exchange membrane fuel cell (PEMFC) by using electrochemical measurement techniques. Interfacial contact resistance(ICR) between the stainless steel and gas diffusion layer(GDL) was also measured. The possibility of 316L was evaluated as a substitute material for the graphite bipolar plate of PEMFC. The value of ICR decreased with an increase in compaction stress(20 N/$cm^2$~220 N/$cm^2$) showing the higher values than the required value in PEMFC condition. Although 316L was spontaneously passivated in simulated cathodic environment, its passive state was unstable in simulated anodic environment. Potentiostatic and electrochemical impedance spectroscopy (EIS) measurement results showed that the corrosion resistance in cathodic condition was higher and more stable than that in anodic condition. Field emission scanning electron microscopy (FE-SEM), and inductively coupled plasma(ICP) were used to analyze the surface morphology and the metal ion concentration in electrolytes.