• Journal of Ocean Engineering and Technology
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• v.34 no.1
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• pp.26-36
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• 2020

An extreme value analysis of metocean data which include wave, wind, and current data is a prerequisite for the operation and survival of offshore structures. The purpose of this study was to provide information about the return wave, wind, and current values for the Barents Sea using extreme value analysis. Hindcast datasets of the Global Reanalysis of Ocean Waves 2012 (GROW2012) for a waves, winds and currents were obtained from the Oceanweather Inc. The Gumbel distribution, 2 and 3 parameters Weibull distributions and log-normal distribution were used for the extreme value analysis. The least square method was used to estimate the parameters for the extreme value distribution. The return values, including the significant wave height, spectral peak wave period, wind speed and current speed at surface, were calculated and it will be utilized to design offshore structures to be operated in the Barents Sea.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.883-886
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• 2008

In optical information technology, an electro-controllable Photonic Band Gap (PBG) in a photonic crystal (PC) material is potentially useful for the manipulation of light. Despite a great deal of research on PBGs, the reliable use of electro-active PBG material systems is restricted to only a few cases because of the complex and limiting nature of the structures involved. Here, we propose a PBG system that uses a liquid crystal (LC) polymer composite. The composite is made of nematic LCs (NLCs) embedded in polymeric helical networks of photo-polymerized cholesteric LCs (CLCs). The composite film shows a large field-induced reversible color shift over 150 nm of the reflection band, due to the reorientational undulation of the helical axis, similar to the Helfrich effect.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.229-235
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• 2018

As of in the year of 2016, 40 million ARM processors are being shipped everyday and more than 86 billion ARM processors are mounted in mobile communications, consumer electronics, enterprises, and embedded systems. Nationally, we are capable of designing high-end memory semiconductors, but not in processors, resulting in unbalance. Generally, highly expensive software programs are necessary for designing processors which makes it difficult to set up proper environments. However, ModelSim simulator provided by Altera is free and everybody can use it. In this paper, the VHDL language which is widely used in Europe, universities, and research centers around the world for the ASIC design is selected for designing 32-bit ARM processor and simulated by ModelSim. As a result, 37 instructions of ARMv4 has been successfully executed.

• The KIPS Transactions:PartA
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• v.10A no.5
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• pp.589-594
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• 2003

In this paper, we exmined the effect of leaner-tutor interaction model implemented in a Web-based virtual education system. Also, we proposed a new tutor model as a strategy for solving problems found in learner-tutor intraction in Web-based virtual education. Then, based on the results of previous research, we derived the roles of the tutor, and using the roles, modeled components of interaction between the tutor based on existing Web-based virtual education systems to demonstrate the effect. The results showed that the proposed model is efficient for improving the learners' achievements and interactive activities.

• Journal of Communications and Networks
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• v.3 no.4
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• pp.297-306
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• 2001

In the last couple of years service management has gained more and more momentum in the research community. Nowadays, as complexity of IT-services is increasing, these services are usually composed of interdependent, layered services hosted by various providers. Therefore, a strong cooperation of providers involved in service provisioning is needed, especially regarding their management processes and systems. One important step is to establish a common understanding about service-related terms in order to be able to specify service functionality and the resulting management tasks. Additionally, means to analyze and identify the necessary actors and the corresponding inter- and intra-organizational relationships are needed. This paper presents an extended version of the MNM service model which provides a generic model defining commonly needed service-related terms, concepts and structuring rules in a general and unambiguous way. Furthermore, we demonstrate the application of the MNM service model by modeling a riser help desk service based on a concrete scenario. The experience gained from modeling is used to discuss the benefits of service modeling in general.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.188-193
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• 2004

3D spatial-modeling can be used in various safety-enhancement applications and for as-built data acquisition in project-control systems. The objective of the research reported herein was to provide spatial-modeling methods that represent construction sites in an efficient manner and to validate the proposed methods by testing them in an actual construction environment. Algorithms to construct construction-site scenes and to carry out coordinate transformations in order to merge data from different acquisition locations are presented. Field experiments were conducted to establish performance parameters and validation for the proposed methods and models. Initial experimental work has demonstrated the feasibility of this approach.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.8
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• pp.418-423
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• 2000

In this paper, we reported the current limiting properties of superconducting fault current limiters (SFCL). Our SFCL was patterned in a coil-type on a YBCO film deposited using rf sputtering techniques and was coated with a gold shunt layer in order to disperse the heat generated at hot spots in the YBCO film. Current increased up to 13.5 Apeak at 60 Hz for the voltage of 11.5 Vpeak, which is the minimum quench point, and increased up to 17.6 Apeak at 60 Hz for the voltage of 80 Vpeak. The quench completion time was 5 msec at 11.5 Vpeak and 4 msec at 80 Vpeak respectively. We think that this architecture using coil-type SFCL can be useful for the protection of the power delivery systems from fault currents.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.7
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• pp.23-28
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• 2010

We propose a reference vector diversity method in multi-cell multi-user uplink system with the subspace interference alignment to obtain higher sum rate capacity. The proposed method transmits several reference vectors before the data transmission, and selects the best reference vector to maximize the cell sum rate. The proposed method provides higher sum-rate capacity compared with the previous interferenc alignment. Simulation result exhibits the proposed method improves the sum-rate capacity by 60%.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.10
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• pp.60-67
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• 1990

This paper proposes a model-based fault detection method for linear/nonlinear system having modelling errors, nonlinearities and measurement noise. The system model is represented by the unified operator [5] in order to apply to both the continuous-time and discrete-time problems. The fault detection method suggested here accounts for the effects of noise, model mismatch and nonlinearities. Modelling errors are depicted by additive forms and the nominal model denominator is fixed via prior experiments in order to quantify the nucertainty bound on the parameter estima-tion. The least square method is used to estimate the numerator parameters of the nominal model. performance than traditional methods.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.3
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• pp.1-7
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• 1999

In this research, transformation-based optimization techniques for pipelined designs have been developed. The transformation-based optimization techniques include pipelined architecture transformations and retiming transformations. The new transformation method has the following three features. First, the overall performance of a pipelined system is optimized owing to various transformations including retiming of multiple pipelined blocks. Second, these techniques can be used to search a large solution space by allowing efficient exploration of trade-offs between area and performance. Third, these techniques can be easily extended to a new transformation or algorithm and can be used to optimize memory or bus architectures. Experimental results illustrate that these transformation-based optimization techniques improve area by 21% and performance by 17% on the average for a set of pipelined designs. Especially, the techniques are useful to efficiently explore a large design space.