• Journal of Ocean Engineering and Technology
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• v.32 no.6
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• pp.466-473
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• 2018

This paper presents an estimation method for the static configuration of a steel lazy wave riser (SLWR) using the dynamic relaxation method applied to estimate the configuration of structures with strong geometric non-linearity. The lumped mass model is introduced to reflect the flexible structural characteristics of the riser. In the lumped mass model, the tensions, shear forces, buoyancy, self-weights, and seabed reaction forces at nodal points are considered in order to find the static configuration of the SLWR. The dynamic relaxation method using a viscous damping formulation is applied to the static configuration analysis. Fictitious masses are defined at nodal points using the sum of the largest direct stiffness values of nodal points to ensure the numerical stability. Various case studies were performed according to the bending stiffness and size of the buoyancy module using the dynamic relaxation method. OrcaFlex was employed to validate the accuracy of the developed numerical method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.2
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• pp.932-945
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• 2018

Everything in the world is becoming connected and interactive due to the Internet. The future of interactive smart environments such as smart cities, smart industries, or smart farms demand high network bandwidth, high network flexibility, and self-organization systems without costly hardware upgrades, and they provide a sustainable, scalable, and replicable smart environment backbone infrastructure. This paper presents a new Hybrid Software-Defined architecture for integrating Internet-of-Things technologies that are essential technologies for smart environments. It combines a software-defined networking infrastructure and a real-time distributed network framework with an advanced optimization to enable self-configuration, self-management, and self-adaption for providing seamless communication and efficiently managing a vast number of smart heterogeneous devices.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.4
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• pp.240-245
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• 2000

The self-field losses in a long multifilamentary Bi-2223/AgMgNi tape with varying transport current, voltage tap configurations, frequency and tape arrangements were investigated. Experimental results show that the measured losses are strongly dependent on voltage gap configurations but independent on tape arrangements. All voltage taps except the center tap are found to agree well with those predicted by Norris for an elliptical conductor. The self-field losses are purely hysteretic in nature in the range of applied frequencies for the transport currents below the critical current.

• Structural Engineering and Mechanics
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• v.32 no.5
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• pp.701-704
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• 2009

• Journal of the Korean Society of Clothing and Textiles
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• v.45 no.5
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• pp.804-824
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• 2021

This study qualitatively explored the case of users utilizing multiple accounts on one social network service to create their own multiple spaces and different personas. The purpose of the study was to understand the behavior of people who use multiple accounts to express their identity online using Carl Jung's personality theory. We used in-depth interviews and the Zaltman metaphor elicitation technique (ZMET), targeting 19 people in their 20s and 30s who use more than one personal account on Instagram. Creating a shared consensus map using the configuration concept of ZMET derived six personas in relation to Instagram accounts. The motivations for the respondents' self-presentation associated with their personas and self-presentation types shown on Instagram were analyzed in terms of persona and fashion and subdivided into five dimensions: relationship management strategic presentation, self-monitoring presentation, competence demonstration presentation, anonymous presentation, and persona-centered presentation. Each respondent's persona and self-presentation formed by the Instagram account was analyzed.

• Structural Engineering and Mechanics
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• v.51 no.5
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• pp.847-866
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• 2014

This paper describes a formulation to predict optimum post-tensioning forces and cable dimensioning for self-anchored cable-stayed suspension bridges. The analysis is developed with respect to both dead and live load configurations, taking into account design constrains concerning serviceability and ultimate limit states. In particular, under dead loads, the analysis is developed with the purpose to calculate the post-tensioning cable forces to achieve minimum deflections for both girder and pylons. Moreover, under live loads, for each cable elements, the lowest required cross-section area is determined, which verifies prescriptions, under ultimate or serviceability limit states, on maximum allowable stresses and bridge deflections. The final configuration is obtained by means of an iterative procedure, which leads to a progressive definition of the stay, hanger and main cable characteristics, concerning both post-tensioning cable stresses and cross-sections. The design procedure is developed in the framework of a FE modeling, by using a refined formulation of the bridge components, taking into account of geometric nonlinearities involved in the bridge components. The results demonstrate that the proposed method can be easily utilized to predict the cable dimensioning also in the framework of long span bridge structures, in which typically more complexities are expected in view of the large number of variables involved in the design analysis.

• The Journal of Korea Robotics Society
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• v.17 no.2
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• pp.238-244
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• 2022

Maintenance works of offshore wind turbines could take a longer time, which causes the reduction of their energy production efficiency, than those of onshore wind turbines owing to severe offshore environment. Subsequently, preventive maintenance measures are required to increase the production efficiency. Thus, we proposed a wheel-based Underwater Pole Climbing Robot (UPCR) platform, which was aimed at the periodic inspection and maintenance of the substructures of the offshore wind turbines, with three advantages: high speed, good mobility and low power consumption. In the proposed platform, a self-locking system using a gripper module was adopted for preventing slippery problem and a dual configuration was chosen for moving on a branched structure. As a result, the proposed robot was able to continuously climb, preserve it's position at the pole without consuming energy, and move from the pole to the other branched pole. The results of this research show that the UPCR has basic moving capabilities required for the underwater work for the substructures of the offshore wind turbines.

• International Journal of Human Ecology
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• v.16 no.2
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• pp.11-20
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• 2015

The purpose of this study was to examine the effects of the construal level and temporal distance of a message and consumer's Social Network Service (SNS) self-efficacy on consumers' attitudes toward SNS fashion advertising. This study employed a 2 (message configuration: high construal level/low construal level) ${\times}$ 2 (temporal distance: distant future/near future) ${\times}$ 2 (SNS self-efficacy: high/low) between-subject factorial design. The survey was conducted on Facebook users in their twenties (N=216). The results are as follows: First, attitude toward SNS fashion advertising and purchase intention was higher when the message construal level was lower and when the temporal distance was closer. Second, no interactions between temporal distance and message construal level for attitude toward SNS advertising and purchase intention were found in this study. However, interactions between temporal distance and SNS self-efficacy for attitude toward SNS advertising and purchase intention were found. When the SNS self-efficacy was high, message with the low construal level reacted significantly positive in terms of attitude toward the ad as well as purchase intention. It is expected that this study will provide insight for apparel makers or retailers to use SNS as a new advertising media for fashion marketing. Practical implications and limitations are discussed.

• Electronics and Telecommunications Trends
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• v.25 no.6
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• pp.144-156
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• 2010

기존 2G/3G 무선 네트워크에서 많은 네트워크 요소들과 관련된 파라미터들이 수동으로 설정되었다. 네트워크 구성 요소들과 이와 관련된 파라미터들의 설계, 설정, 통합 및 관리 기능은 효율적이고 신뢰성 있는 네트워크 운용을 위하여 매우 중요하다. 그러나, 이들 네트워크 파라미터 조정에는 전문적인 엔지니어의 수작업이 필요하다. 이러한 수작업 과정은 시간이 많이 걸리고 잠재적으로 수작업에 따른 오류 발생 가능성이 있다. 이동 통신 시스템에서 펨토셀 및 차세대 4G 도입이 가시화됨에 따라, 기지국의 설치 및 운용 과정에서 Self-Configuration, Self-Optimization 및 Self-Healing과 같은 자동화 기능을 포함하는 SON 기술에 대한 관심이 높아지고 있다. 본 고에서는 LTE에서의 SON 기술 관련 주요 기술적 내용을 정리하고, 표준화 동향 및 업체 기술 동향에 대하여 살펴보고자 한다.

• Current Optics and Photonics
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• v.2 no.1
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• pp.23-26
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• 2018

Optical-layer restoration has been demonstrated with a wavelength-blocker (WB) -based reconfigurable optical add/drop multiplexer (ROADM). Two $2{\times}2$ optical switches with a control circuit were placed before and after a WB-based ROADM to provide automatic path restoration under fiber-failure conditions. Using the proposed node configuration, a 3-node self-healing ring (SHR) network has been implemented to demonstrate the feasibility of the automatic optical-layer restoration. From the results, the restoration time was measured to be ~4 ms under fiber-failure conditions, without any additional power penalty in receiver sensitivity.