• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.584-588
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• 1991

This paper presents a fuzzy adaptive controller which can improve the control policy automatically. Adaptation is achieved by the addition of on-line identification of the fuzzy inverse model using input-output data pairs of the process. Starting with an initial crude control rule, the adaptive controller matches the model to the process to self-tune the controller. The control algorithm needs much less memory of computer than other SOC algorithms.

• Vacuum Magazine
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• v.3 no.2
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• pp.17-20
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• 2016

Piezoelectric nanogenerators are energy harvesting device to convert a mechanical energy into an electric energy using nanostructured piezoelectric materials. This review summarizes works to date on piezoelectric nanogenerators, starting with a basic theory of piezoelectricity and working mechanism, and moving through the reports of numerous nanogenerators using nanorod arrays, flexible substrates and alternative materials. A sufficient power generated from nanogenerators suggests feasible applications for either power supplies or strain sensors of highly integratedl nano devices. Further development of nanogenerators holds promise for the development of self-powered implantable and wearable electronics.

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.245-246
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• 2008

• Proceedings of the IEEK Conference
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• 2001.06c
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• pp.199-202
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• 2001

In this paper, we proposed and analyzed a new class of irregular fault-tolerant multistage interconnection network named as Extended-QT(Quad Tree) network. E-QT network is extended QT network. A unique path MIN usually is low hardware complexity and control algorithm. So we proposes a class of multipath MIN which are obtained by adding self-loop auxiliary links at the a1l stages in QT(Quad Tree) networks so that they can provide more paths between each source-destination pair. The routing of proposed structure is adaptived and is based by a routing tag. Starting with the routing tag for the minimum path between a given source-destination pair, routing algorithm uses a set of rules to select switches and modify routing tag. Trying the self-loop auxiliary link when both of the output links are unavailable. If the trying is failure, the packet discard. In simulation, an index of performance called reliability and cost are introduced to compare different kinds of MINs. As a result, the prouosed MINs have better capacity than 07 networks.

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.110-112
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• 2008

A linear generator driven by a hydrogen combustion engine has been developed. Unlike rotary engine-generator systems, the linear counterpart is inherently unable to start by itself unless external force is provided for initial compression/ignition cycle. When the generator is connected to utility power lines through a bidirectional power conversion system, however, the self start-up can be done by driving the generator as a motor. This paper introduces a prototype 1kW linear hydrogen engine-generator system being developed and shows the self start-up is possible with proper motoring mode.

• Industry Promotion Research
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• v.1 no.1
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• pp.151-157
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• 2016

Nowadays Chinese society advocates a kind of principal thinking, which Chinese call it "harmony". The entire Chinese society is trying to build a so-called "harmonious society", that is, people live in harmony with the natural environment and carry out sustainable development; people live in harmony with others and build harmonious social relationships; people live in harmony with themselves and cultivate self-morality and enhance national self-quality. It can be seen that the word "harmony" runs through this thinking all the time. This paper aims at viewing Chinese people's philosophy in Ming Dynasty from the Piaohailu. Likewise, the starting points of the paper are also these three aspects which are people's relationships with nature, others and themselves. Based on this angle, it tries to conduct a simple analysis and study by taking Korean official Cui Pu's Piaohailu as the main historical data.

• Journal of Korean Academy of Nursing Administration
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• v.12 no.2
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• pp.276-286
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• 2006

Purpose: The purpose of this study was to analyze the effects of self-efficacy and collective-efficacy on job stress in the nursing staff. Method: This study surveyed 160 nurses in three general hospitals in the Seoul and Gyung-gi province for two months starting in September 2004. The questionnaire consisted of 54 questions about job stress, 10 questions about self-efficacy, and 7 questions about collective-efficacy. The answers were on a scale rating of 5. The answer sheets were analyzed with descriptive statistics, the t-test, ANOVA, the tukey test, the Pearson correlation coefficients and stepwise multiple regression using SAS version 8.2. Result: The average job stress rating of the nurses was 3.11. The average self-efficacy and the average collective-efficacy were 3.41 and 3.39, respectively. The age, working department, income level, shift-work and hospital have influence on job stress. Efficacies such that self-efficacy and collective-efficacy have influence on job stress. The much efficacy makes the less job stress. The stepwise multiple regression revealed that the significant predictor of job stress was working department and hospital. Conclusion: This study showed that collective-efficacy as well as self-efficacy reduces job stress, so nursing intervention methods should promote collective-efficacy. The collective-efficacy improvement program should be developed to improve job performance, to improve cohesion of nursing units, and to improve satisfaction on the job. The next research could be to develop collective-efficacy improvement programs for nursing units.

• Journal of the Korean housing association
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• v.19 no.2
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• pp.31-42
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• 2008

Research outcome shows the following: 1. Estimation by the year 2015 on the number of the aged people and on the number of the household of living alone and living with spouse only, per age-cohort by 5 years, per basic self-govern-ins local groups and the city of Daegu. The result is supposed to serve as meaningful basic material in building up future policies in many areas for the aged people living in their homes. 2. Estimation varies according to the areas and the age-cohorts. In urban areas, increase of the numbers of the households of the aged people living alone and living with spouse only is estimated in every age-cohort. In rural areas, variance between two age-groups, old-old and young-old, is observed. Both of the numbers of the households for the aged living alone and the aged living with spouse only have increased continuously by the year 2005. But the hither-to increase tendency is estimated to reverse itself to a decrease starting from the younger within the young-old age group, and the ratio of the old-old age-group in rural population will sharply increase starting from the year 2005. Such increase in the number of the aged people in need of the housing and the social support requires the increasing policy consideration for the issue of housing for the aged living in their homes. In spite of the decreasing tendency in the number of the aged people living alone and living with spouse only in rural areas, still there will continue to be more number of such households than in urban area for the time being. The government of Gyeongsangbuk-Do should pay more consideration to the old-old aged living alone and living with spouse only in rural areas, while being prepared for the sharply increasing households for the aged living alone and living with spouse only in urban areas.

• Wind and Structures
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• v.17 no.6
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• pp.647-670
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• 2013

The paper presents a numerical approach to study of fluid flow characteristics and to predict performance of wind turbines. The numerical model is based on Finite-volume method (FVM) discretization of unsteady Reynolds-averaged Navier-Stokes (URANS) equations. The movement of turbine blades is modeled using moving mesh technique. The turbulence is modeled using commonly used turbulence models: Renormalization Group (RNG) k-${\varepsilon}$ turbulence model and the standard k-${\varepsilon}$ and k-${\omega}$ turbulence models. The model is validated with the experimental data over a large range of tip-speed to wind ratio (TSR) and blade pitch angles. In order to demonstrate the use of numerical method as a tool for designing wind turbines, two dimensional (2-D) and three-dimensional (3-D) simulations are carried out to study the flow through a small scale Darrieus type H-rotor Vertical Axis Wind Turbine (VAWT). The flows predictions are used to determine the performance of the turbine. The turbine consists of 3-symmetrical NACA0022 blades. A number of simulations are performed for a range of approaching angles and wind speeds. This numerical study highlights the concerns with the self-starting capabilities of the present VAWT turbine. However results also indicate that self-starting capabilities of the turbine can be increased when the mounted angle of attack of the blades is increased. The 2-D simulations using the presented model can successfully be used at preliminary stage of turbine design to compare performance of the turbine for different design and operating parameters, whereas 3-D studies are preferred for the final design.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1273-1283
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• 2011

A 3-dimensional unsteady numerical analysis has been performed to evaluate the aerodynamic characteristics of a Giromill. Generally, the structure of a Giromill is simple and therefore easy to develop. In addition, the high solidity of the Gironmill helps improve the self-starting capacity at a low tip speed ratio (TSR). However, contrary to the Darrieus wind turbine which has a TSR of 4-7, a Giromill has a low TSR of 1-3. In this study, the aerodynamic characteristics of the Giromill are investigated using computational fluid dynamics (CFD). Three straight-bladed wings are used, and the solidity of the Giromill is 0.75. In contrast to a Darrieus wind turbine having low solidity, the Giromill shows a sudden decrease in the aerodynamic performance because of the interference between the wings and an increase in the drag on the wings in the downstream direction where wind flow is significantly reduced. Consequently, the aerodynamic performance decreased at a TSR value lower than 2.4.