• Wind and Structures
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• v.18 no.6
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• pp.693-715
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• 2014

Stochastic processes are used to represent phenomena in many diverse fields. Numerical simulation method is widely applied for the solution to stochastic problems of complex structures when alternative analytical methods are not applicable. In some practical applications the stochastic processes show non-Gaussian properties. When the stochastic processes deviate significantly from Gaussian, techniques for their accurate simulation must be available. The various existing simulation methods of non-Gaussian stochastic processes generally can only simulate super-Gaussian stochastic processes with the high-peak characteristics. And these methodologies are usually complicated and time consuming, not sufficiently intuitive. By revealing the inherent coupling effect of the phase and amplitude part of discrete Fourier representation of random time series on the non-Gaussian features (such as skewness and kurtosis) through theoretical analysis and simulation experiments, this paper presents a novel approach for the simulation of non-Gaussian stochastic processes with the prescribed amplitude probability density function (PDF) and power spectral density (PSD) by amplitude modulation and phase reconstruction. As compared to previous spectral representation method using phase modulation to obtain a non-Gaussian amplitude distribution, this non-Gaussian phase reconstruction strategy is more straightforward and efficient, capable of simulating both super-Gaussian and sub-Gaussian stochastic processes. Another attractive feature of the method is that the whole process can be implemented efficiently using the Fast Fourier Transform. Cases studies demonstrate the efficiency and accuracy of the proposed algorithm.

• Bulletin of the Korean Mathematical Society
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• v.44 no.1
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• pp.173-176
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• 2007

The non-existence is proved of four-dimensional mod 2 semisimple representations of Gal ($\=\mathbb{Q}/\mathbb{Q}$) which are unramified outside 2.

• Kyungpook Mathematical Journal
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• v.61 no.2
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• pp.213-222
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• 2021

In this paper we investigate the Baer-Kaplansky theorem for module classes on algebras of finite representation types over a field. To do this we construct finite dimensional quiver algebras over any field.

• Wind and Structures
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• v.29 no.6
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• pp.389-403
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• 2019

In this study, two original spectral representations of stationary stochastic fields, say the continuous proper orthogonal decomposition (CPOD) and the frequency-wavenumber spectral representation (FWSR), are derived from the Fourier-Stieltjes integral at first. Meanwhile, the relations between the above two representations are discussed detailedly. However, the most widely used conventional Monte Carlo schemes associated with the two representations still leave two difficulties unsolved, say the high dimension of random variables and the incompleteness of probability with respect to the generated sample functions of the stochastic fields. In view of this, a dimension-reduction model involving merely one elementary random variable with the representative points set owing assigned probabilities is proposed, realizing the refined description of probability characteristics for the stochastic fields by generating just several hundred representative samples with assigned probabilities. In addition, for the purpose of overcoming the defects of simulation efficiency and accuracy in the FWSR, an improved scheme of non-uniform wavenumber intervals is suggested. Finally, the Fast Fourier Transform (FFT) algorithm is adopted to further enhance the simulation efficiency of the horizontal stochastic wind velocity fields. Numerical examplesfully reveal the validity and superiorityof the proposed methods.

• The Journal of Art Theory & Practice
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• no.10
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• pp.183-202
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• 2010

The term "philosophizing art" was coined by Arthur Danto, who tried to define new forms of art, especially Andy Warhol's pop art appeared in New York after 1960's, which could not be explained by traditional concept of "representation". As Danto said "the term 'philosophizing art' is unclear, whether art discusses philosophical issues or art is the object of philosophic discussions", it does not seem like Danto himself had a specific idea when he used this term. The background for Danto coining this term derives from the fact that the old art concept such as denotation and connotation could not fully explain phenomenalistic aspects of concept art which appeared frequently at that time. Many articles in his book "philosophizing art", in which many of his criticism are included, mainly say that art begins philosophizing by dealing with not mimesis or representation but concepts. According to his argument, the history of western art, which has been consisted of mimesis and representation, has come to end when art is about physically embodied with meaning. Of course, as Danto say so, what goes to end is not art itself, but the narrative of art. It means master narrative saying art should be shown different from nature or artificial daily product is over. Danto could not find principals of mimesis and representation which had been main logic in the western art history, when he saw Andy Warhol's Brillo Boxes at Stable Gallery, New York in 1964. Danto questioned "if we can not distinguish Brillo box's artistic aspects visually from other factory-made products, how can we distinguish art from non-art", By answering those questions, he discovered two facts which made him realize the end of Art: One is there is no special way in which works of art have to be shown or has to exist. Therefore, art history has proven that commercial boxes, trashes and files of underwear can be a work of art. The other is we have fully recognized it at the end of 20thcentury. Danto confessed that through Brillo Boxes, he realized the works of art are decided by something can not be seen by eyes, not by distinguished differences by looking at it. This thesis is trying to show personal understanding about art, philosophy and discourses surrounding them and to figure out how Dante opened a new world to art criticism by using new definitions such as 'end of art' and 'philosophizing art' which Danto used to explain inner aspects of art.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.2
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• pp.37-52
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• 2010

The main purpose of this study is to examine how place representation is related to the formation of urban parks in Seoul, which began at the end of the 19th century. In order to grasp place representation, the hypothesis of this study is that most urban parks are undertaken with the idea of monumentality and symbolism or memories of the place itself. Diverse ways of representation through physical or non-physical aspects of symbolism, monumentality, and place memory are summarized as follows. First, in the case of the physical aspects of representation in the parks, monumentality and symbolism are expressed mostly through monuments or statues. In the case that the intention of the park is commemorative, celebrative elements are more actively utilized. In other cases, symbolic sculptures or statues, which are randomly designated by the government, are so often used regardless of the overarching concept of the urban park. In addition, in the case of place memory, monumentality or symbolism are commonly represented through bronze statues or partial remnants of the past. Recently, however, the site in itself has been constructed to coordinate the memories of a certain place into the configuration of the park. Secondly, in relation to the non-physical representation elements, many urban parks tend to reveal monumentality or symbolism through the names they are given. Recently, this tendency has significantly dropped, but some places of parksare frequently denominated in consideration of place memory. In the case of events held in parks, parks which were constructed in the beginning of the park movement, such as Tapgol Park, hold certain events to commemorate certain causes that took place in those days. On the other hand, the main purpose of recently-constructed urban parks relating to place memory is to encourage citizens to participate in events in a variety of ways.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.3
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• pp.81-86
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• 2010

Since CORDIC (COordinate Rotation DIgital Computer) is able to carry out the phase operation, such as vector to phase conversion or rotation of vectors, with adders and shifters, it is well suited for the design of the frequency synchronization unit in OFDM receivers. It is not easy, however, to fully utilize the CORDIC in the OFDM demodulator because of the non-linear characteristics of the direction sequence (DS), which is the representation of the phase in CORDIC. In this paper a new representation method is proposed to linearize the direction sequence approximately. The maximum phase error of the linearized binary direction sequence (LBDS) is also discussed. For the purpose of designing the hardware, the architectures for the binary DS (BDS) to LBDS converter and the LBDS to BDS inverse converter are illustrated. Adopting LBDS, the overall frequency synchronization hardware for OFDM receivers can be implemented fully utilizing CORDIC and general arithmetic operators, such as adders and multipliers, for the phase estimation, loop filtering of the frequency offset, derotation for the frequency offset correction. An example of the design of 22 bit LBDS for the T-DMB demodulator is also presented.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.2
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• pp.124-133
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• 2009

There are many different ID representation forms depending on the media or applications. In case of RFID tag, ID representation form must be followed by the rule of ISO/IEC 15962. In this study, we developed the efficient ID conversion algorithm between ID representation form on RFID tag and Internet. The main idea is on the use of XML based ID profiles and three step logical IDs forms. The algorithm was tested by the typical three kinds of real IDs such as EPC, ISO/IEC 15459 KKR Code, and mCode which are the typical meta-IDs can be defined in ISO/IEC 18000-6C tag.

• Proceedings of the Korea Database Society Conference
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• 1997.10a
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• pp.483-503
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• 1997

One important question that arises when dealing with temporal databases in context of object-oriented systems is the method that associates time with attributes relationship semantics. Results of previous work about attribute versioning, particularity extending flat(First Normal Form: FNF) or nested(Non-First Normal Form: NFNF) relational models. are not applicable to temporal object-oriented databases. This is because object-oriented models provide more powerful constructs than traditional models for structuring complex objects. Therefore, this paper presents an formal approach for incorporating temporal extension to object-oriented databases. Our goal in this paper is to study temporal object-oriented database representation according to generalization, aggregation and association among objects. We define tile concepts of attribute versioning in temporal object-oriented model, and we concentrate on the representation of temporal relationship among objects. Another contribution of this paper is to specify time constraints on relationship semantics and analyze our model based on representation criteria. By means of formalizing tile temporal object oriented model, this paper can not only provide tile robust operating functions that design algebraic operators, but also entrance the reuse of modules.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.5
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• pp.747-754
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• 2001

This paper describes measurement of relative permittivity of illite found in young-dong area. A measurement of relative permittivity of the illite was made using cylindrical cavity resonators with a moveable cap. A concentric dielectric-rod inserted the cylindrical cavity resonator and an exact field representation of non-decaying mode of the resonator are introduced for the measurement of relative permittivity. The exact electromagnetic fields in cylindrical cavity with a concentric dielectric rod is analysed. The relative permittivity of dielectric in the cavity is calculated by analyzing a characteristic equation. The characteristic equation is solved by using the ContourPlot graph of Mathematica. We know that the field representation of non-decaying mode is exact. As a result, the relative permittivity of dielectric materials was 7.820 for a sample with binder and 7.894 for a pure sample.