• The Journal of Korea Robotics Society
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• v.12 no.3
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• pp.332-338
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• 2017

As an interpretation of existing jamming effects, the main variables affecting the increase in stiffness due to jamming are known as system density, jamming density, pressure, and particulate temperature. The main variable, jamming density, is closely related to the distribution of particle size and contact properties such as particle shape and friction. However, the complexity of these variables makes it difficult to fully understand the mechanism of the jamming effect. In this paper, we focus on the jamming effects of particles that have more elastic properties than particles such as sand and coffee powder, which are commonly used as constituent particles of existing jamming, in order to reduce complicated factors such as temperature and concentrate on jamming effects based on elastic characteristics of particles. It was experimentally explored the possibility of increasing stiffness by mixing particles of different sizes rather than simply increasing the bending stiffness by controlling the particle size. Through simulations and experiments, we found a case where the stiffness of each particle size distribution is larger than the stiffness of each particle size.

• Journal of Korea Multimedia Society
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• v.14 no.6
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• pp.711-718
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• 2011

The k-Nearest Neighbor classifier that does not require a training phase is appropriate for a variable number of classes problem like face recognition, Recently distance metric learning methods that is trained with a given data set have reported the significant improvement of the kNN classifier. However, the performance of a distance metric learning method is variable for each application, In this paper, we focus on the face recognition and compare the performance of the state-of-the-art distance metric learning methods, Our experimental results on the public face databases demonstrate that the Mahalanobis distance metric based on PCA is still competitive with respect to both performance and time complexity in face recognition.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1597_1598
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• 2009

In this paper, the techniques and design focus of flexible gain coltrol of LAN(Low Noise Amplifier) using the TSMC 0.18um CMOS process. The design frequency set up a standard on 2.4GHz that is used in Zigbee system. The design concepts a basic Cascode LNA techniques and a swiching circuit consisted of 4 NMOS of load resistance, which convert the output impedenceby tuning on or off. The result show the gain change by NMOS operated swich. The simulation result is that Gain is 10.23~12.96dB and NF(Noise Figure) is 1.41~1.47dB.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.2
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• pp.198-209
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• 1999

This study reports the selection of dependent variables for momentum equations in general curvilinear coordinates. Catesian, covariant and contravariant velocity components were examined for the dependent variable. The focus of present study is confined to staggered grid system Each dependent variable selected for momentum equations are tested for several flow fields. Results show that the selection of Cartesian and covariant velocity components intrinsically can not satisfy mass conservation of control volume unless additional converting processes ore used. Also, Cartesian component can only be used for the flow field in which main-flow direction does not change significantly. Convergence rate for the selection of covariant velocity component decreases quickly as with the increase of non-orthogonality of grid system. But the selection of contravariant velocity component reduces the total mass residual of discretized equations rapidly to the limit of machine accuracy and the solutions are insensitive to the main-flow direction.

• Korean Journal of Construction Engineering and Management
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• v.21 no.1
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• pp.12-20
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• 2020

To estimate collusion effects on bid award in Public Construction works, this paper uses Logit Model, which is a choice variable model. Price, design, competition, and other factors are included, with a special focus on collusion, as independent variables in the model. The empirical results are as follows. First, collusion has little effects on bid award, but great impacts on bidding behavior. Secondly, the score of design is the most important and significant factors among all variables. Thirdly, competition has also significant effects on bid award. Finally it is analyzed that institutional framework and characteristics of public work have some effects on bidding award.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1996.06a
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• pp.139-156
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• 1996

The phase field model is becoming the model of choice for the theoretical study of the morphologies of crystals growth from the melt. This model provides an alternative approach to the solution of the classical (sharp interface) model of solidification by introducing a new variable, the phase field, Ø, to identify the phase. The variable Ø takes on constant values in the bulk phases and makes a continuous transition between these values over a thin transition layer that plays the role of the classically sharp interface. This results in Ø being governed by a new partial differential equation(in addition to the PDE's that govern the classical fields, such as temperature and composition) that guarantees (in the asymptotic limit of a suitably thin transition layer) that the appropriate boundary conditions at the crystal-melt interface are satisfied. Thus, one can proceed to solve coupled PDE's without the necessity of explicitly tracking the interface (free boundary) that would be necessary to solve the classical (sharp interface) model. Recent advances in supercomputing and algorithms now enable generation of interesting and valuable results that display most of the fundamental solidification phenomena and processes that are observed experimentally. These include morphological instability, solute trapping, cellular growth, dendritic growth (with anisotropic sidebranching, tip splitting, and coupling to periodic forcing), coarsening, recalescence, eutectic growth, faceting, and texture development. This talk will focus on the fundamental basis of the phase field model in terms of irreversible thermodynamics as well as it computational limitations and prognosis for future improvement. This work is supported by the National Science Foundation under grant DMR 9211276

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5C
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• pp.673-682
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• 2004

The adaptive beam-forming is promising approach for noise reduction in hearing aids. This approach has come in the focus of interest only recently, because of the availability of new and powerful digital signal processors. The adaptation U using usually a Least Mean Squares algorithm, updates the weight vector. In this Paper, we propose a fast wavelet based adaptive algorithm using variable step size algorithm which varies adaptive constant by the change of signal environment. We compared the performance of the proposed algorithm with the known adaptive algorithm using computer simulation of multi channel adaptive bemformer in hearing aids. As the result the proposed algorithm is suitable for adaptive signal processing area using hearing aids and has advantages reducing computational complexity. And we show the beam-forming system using proposed algorithm converges stably in a sudden change of system environment.

• Women's Health Nursing
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• v.21 no.1
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• pp.55-70
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• 2015

Purpose: This study aimed to describe knowledge status of current research related to maternal adaptation of women immigrants by marriage in Korea. Methods: Eighteen quantitative current researches published from January, 2006 to August, 2014 that met the inclusion and exclusion criteria. These 18 articles finally selected for systemic review from 5,168 articles. All current researches included the mother within one year after childbirth and one variable related to maternal adaptation at least. Results: Variables related to psychological adaptation (48.1%) were mostly studied. In detail, parenting stress (17.3%) and parenting competency (15.4%) were frequently surveyed. Also, social support (7.7%), husband rearing support (5.8%) of relational adaptation, and acculturation (3.8%) of cultural adaptation were importantly studied. In addition, frequently used instruments for each study variable were analyzed and evaluated. As major results, parenting stress and parenting efficacy were significantly influenced by social support or husband rearing support and acculturation, and had an effect on parenting behaviors. Various maternal education programs were effective in improving maternal role confidence or parenting efficacy and decreasing parenting stress. Conclusion: Nursing intervention programs for improving maternal adaptation should focus on decreasing parenting stress and increasing parenting efficacy by improving social support and acculturation level of women immigrants by marriage in Korea.

• Korean Journal of Adult Nursing
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• v.24 no.3
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• pp.253-265
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• 2012

Purpose: The focus of this research was a systematic review of published articles and theses for a degree in Korea and foreign countries on rehabilitation therapy for patients with total knee arthroplasty (TKA). Methods: The literature until December in 2011 were searched and the data basis included Medline, CINAHL, KERIS, National Library of Korea, and National Assembly Library web sites. Words for the search were TKA or TKA and rehabilitation. Studies included randomized controlled and non-equivalent control group pretest-posttest design. 31 studies were analyzed focusing on type, application method, dependant variable and effect using descriptive statistics. Results: Seventeen rehabilitation therapies and forty-nine dependant variables were used. The application methods of rehabilitation therapy were diverse. The most frequently used rehabilitation type was an exercise therapy and a pain/discomfort was the most frequently used dependant variable. The effects of rehabilitation therapy were inconsistent. Conclusion: The individualized rehabilitation therapy must be comprised of type, time, frequency, period and duration. Attention must be made as to the research design, especially the better measurement of the dependent variables. This review may serve as a base for future research.

• Journal of the Korea Furniture Society
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• v.24 no.3
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• pp.247-256
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• 2013

A dormitory is the most important compound space to college students who have to live with others. Also, for the students living in the boarding area, the dorm space can be the space for learning, exchanges and cultural. These Housing environment is a public space, so this is based on Universal Design. However, the 1970s-built dormitory space for the current user is narrow and not right for furniture standard. In this study, in order to compensate for these problems, the design directions are based on the previous studies - Park, Young-Soon, 2008, 'A Proposal on Dormitory Furniture Design for University Students.' Based on the previous study, the type of variable design is designed for desks, bookcases, beds, wardrobes, and other cabinets as representative household types. Furthermore, these furnitures are assembled and transformed depend on the dormitory space for single, double and four students. The furniture assembly system and arrangement module are presented in the direction of three kinds of designs. Therefore, three meaning of this study are the development of design to be used each item, the realization of custom furniture for space and presenting variable design module.