• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.1
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• pp.21-36
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• 2018

The incidence of collision damage models on oil tanker and bulk carrier reliability is investigated considering the IACS deterministic model against GOALDS/IMO database statistics for collision events, substantiating the probabilistic model. Statistical properties of hull girder residual strength are determined by Monte Carlo simulation, based on random generation of damage dimensions and a modified form of incremental-iterative method, to account for neutral axis rotation and equilibrium of horizontal bending moment, due to cross-section asymmetry after collision events. Reliability analysis is performed, to investigate the incidence of collision penetration depth and height statistical properties on hull girder sagging/hogging failure probabilities. Besides, the incidence of corrosion on hull girder residual strength and reliability is also discussed, focussing on gross, hull girder net and local net scantlings, respectively. The ISSC double hull oil tanker and single side bulk carrier, assumed as test cases in the ISSC 2012 report, are taken as reference ships.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.6
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• pp.75-87
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• 2023

This study presents an experimental design for demonstrating the role of nature-based solutions to climate change in the landscape and garden sector. The study suggests spatial strategies for a carbon-neutral society and its role as a cultural industry. This paper describes the use of a low-maintenance garden as part of a strategy for carbon reduction with the goal of protecting the environment and forming a carbon-neutral society. To this end, this study involved the design and construction of a realistic model garden to provide scientific data on the functions, spatial elements, and carbon neutrality of carbon-reducing gardens. The target site is located in the Sejong National Arboretum. The test area in which the carbon-reducing function is measured is located in the centre of the site, and other spaces include dry gardens, community gardens, and flower gardens intended for exhibition and relaxation. The experimental area is divided into several smaller areas within which the carbon-reducing effect is analysed according to the amount of biochar installed, the planting density, and the plant species present. The application of facilities and construction methods to promote carbon reduction were based on the method known as '10 types of carbon gardening for the earth'. In the model garden, we employed rainwater utilization facilities and used low-carbon certified wood and local materials. The carbon reduction effect of each facility and construction method is compared and presented here. The results are expected to serve as an important basis for realizing a carbon-neutral society and can be used as a reference in various fields that require sustainable development, such as the garden industry.

• Journal of Power Electronics
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• v.15 no.1
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• pp.190-201
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• 2015

This paper uses the switching function approach to present a simple state model of the Vienna-type rectifier. The approach introduces the relationship between the DC-link neutral point voltage and the AC side phase currents. A novel direct power control (DPC) strategy, which is based on the sliding mode control (SMC) for Vienna I rectifiers, is developed using the proposed power model in the stationary ${\alpha}-{\beta}$ reference frames. The SMC-based DPC methodology directly regulates instantaneous active and reactive powers without transforming to a synchronous rotating coordinate reference frame or a tracking phase angle of grid voltage. Moreover, the required rectifier control voltages are directly calculated by utilizing the non-linear SMC scheme. Theoretically, active and reactive power flows are controlled without ripple or cross coupling. Furthermore, the fixed-switching frequency is obtained by employing the simplified space vector modulation (SVM). SVM solves the complicated designing problem of the AC harmonic filter. The simplified SVM is based on the simplification of the space vector diagram of a three-level converter into that of a two-level converter. The dwelling time calculation and switching sequence selection are easily implemented like those in the conventional two-level rectifier. Replacing the current control loops with power control loops simplifies the system design and enhances the transient performance. The simulation models in MATLAB/Simulink and the digital signal processor-controlled 1.5 kW Vienna-type rectifier are used to verify the fast responses and robustness of the proposed control scheme.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.4
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• pp.333-341
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• 2013

In this paper, a feedback linearization control is proposed to regulate the output voltages of a three-phase four-wire inverter under the unbalanced and nonlinear load conditions. First, the nonlinear model of system including the output LC filters is derived in the d-q-0 synchronous reference frame. Then, the system is linearized by the multi-input multi-output feedback linearization. The tracking controllers for d-q-0-components of three-phase line-to-neutral load voltages are designed by linear control theory. The experimental results have shown that the proposed control method gives the good performance in response to the load conditions.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4134-4145
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• 2022

The collimator is one of the high-heat-flux components used to avoid a series of vacuum and thermal problems. In this paper, the heat load distribution throughout the collimator is first calculated through experimental data, and a transient thermodynamic simulation analysis of the original model is carried out. The error of the pipe outlet temperature between the simulated and experimental values is 1.632%, indicating that the simulation result is reliable. Second, the model is optimized to improve the heat transfer performance of the collimator, including the contact mode between the pipe and the flange, the pipe material and the addition of a twisted tape in the pipe. It is concluded that the convective heat transfer coefficient of the optimized model is increased by 15.381% and the maximum wall temperature is reduced by 16.415%; thus, the heat transfer capacity of the optimized model is effectively improved. Third, to adapt the long-pulse steady-state operation of the experimental advanced superconducting Tokamak (EAST) in the future, steady-state simulations of the original and optimized collimators are carried out. The results show that the maximum temperature of the optimized model is reduced by 37.864% compared with that of the original model. The optimized model was changed as little as possible to obtain a better heat exchange structure on the premise of ensuring the consumption of the same mass flow rate of water so that the collimator can adapt to operational environments with higher heat fluxes and long pulses in the future. These research methods also provide a reference for the future design of components under high-energy and long-pulse operational conditions.

• Journal of the Ergonomics Society of Korea
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• v.36 no.3
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• pp.255-265
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• 2017

Objective: This study aims to survey visual search performance models to assess and predict individual's visual tasks in everyday life and industrial sites. Background: Visual search is one of the most frequently performed and critical activities in everyday life and works. Visual search performance models are needed when designing or assessing the visual tasks. Method: This study was mainly based on survey of literatures related to ergonomics relevant journals and web surfing. In the survey, the keywords of visual search, visual search performance, visual search model, etc. were used. Results: On the basis of the purposes, developing methods and results of the models, this study categorized visual search performance models into six groups: probability-based models, SATO models, visual lobe-based models, computer vision models, neutral network-based models and detection time models. Major models by the categories were presented with their advantages and disadvantages. More models adopted the accuracy among two factors of accuracy and speed characterizing visual tasks as dependent variables. Conclusion: This study reviewed and summarized various visual search performance models. Application: The results would be used as a reference or tool when assessing the visual tasks.

• Journal of Korean Institute of Industrial Engineers
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• v.25 no.2
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• pp.266-273
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• 1999

The maximum work capacity at various shoulder angles was estimated in terms of joint moment through maximum voluntary contraction (MVC) measurement, and the result was compared to workload computed from 3-D static lifting model (3DSSPP) based upon national institute of safety and health (NIOSH) lifting guideline (1991). The electromyography (EMG) of anterior/posterior deltoid and trapezius muscle was also recorded to study the function of individual muscle during asymmetric shoulder lifting. Psychophysical workload was measured to observe the difference from MVC or biomechanical estimation. An apparatus was constructed for the study and twenty five trials including five flexion angles and five add/abduction angles were performed isometrically. Results indicated that MVC at 30 degree of flexion was the strongest whereas MVC at 120 degree was the weakest. In case of add/abduction, MVC decreased to 77 to 89 % during add/abduction compared to the MVC at neutral position. Regarding the normalized EMG value, a substantial increase was observed at 30 and 60 degree abduction. More importantly, the shoulder moment computed from maximum permissible limit (MPL) was greater than the moment at MVC condition during 30 degree adduction. Current result can be used as a reference information for a safe workplace design to prevent the shoulder from an excessive work load in industry.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.23 no.4
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• pp.153-178
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• 2018

Most operational uses of wind speed data require measurements at, or estimates generated for, the reference height of 10 m above mean sea level (AMSL). On the Ieodo Ocean Research Station (IORS), wind speed is measured by instruments installed on the lighthouse tower of the roof deck at 42.3 m AMSL. This preliminary study indicates how these data can best be converted into synthetic 10 m wind speed data for operational uses via the Korea Hydrographic and Oceanographic Agency (KHOA) website. We tested three well-known conventional empirical neutral wind profile formulas (a power law (PL); a drag coefficient based logarithmic law (DCLL); and a roughness height based logarithmic law (RHLL)), and compared their results to those generated using a well-known, highly tested and validated logarithmic model (LMS) with a stability function (${\psi}_{\nu}$), to assess the potential use of each method for accurately synthesizing reference level wind speeds. From these experiments, we conclude that the reliable LMS technique and the RHLL technique are both useful for generating reference wind speed data from IORS observations, since these methods produced very similar results: comparisons between the RHLL and the LMS results showed relatively small bias values ($-0.001m\;s^{-1}$) and Root Mean Square Deviations (RMSD, $0.122m\;s^{-1}$). We also compared the synthetic wind speed data generated using each of the four neutral wind profile formulas under examination with Advanced SCATterometer (ASCAT) data. Comparisons revealed that the 'LMS without ${\psi}_{\nu}^{\prime}$ produced the best results, with only $0.191m\;s^{-1}$ of bias and $1.111m\;s^{-1}$ of RMSD. As well as comparing these four different approaches, we also explored potential refinements that could be applied within or through each approach. Firstly, we tested the effect of tidal variations in sea level height on wind speed calculations, through comparison of results generated with and without the adjustment of sea level heights for tidal effects. Tidal adjustment of the sea levels used in reference wind speed calculations resulted in remarkably small bias (<$0.0001m\;s^{-1}$) and RMSD (<$0.012m\;s^{-1}$) values when compared to calculations performed without adjustment, indicating that this tidal effect can be ignored for the purposes of IORS reference wind speed estimates. We also estimated surface roughness heights ($z_0$) based on RHLL and LMS calculations in order to explore the best parameterization of this factor, with results leading to our recommendation of a new $z_0$ parameterization derived from observed wind speed data. Lastly, we suggest the necessity of including a suitable, experimentally derived, surface drag coefficient and $z_0$ formulas within conventional wind profile formulas for situations characterized by strong wind (${\geq}33m\;s^{-1}$) conditions, since without this inclusion the wind adjustment approaches used in this study are only optimal for wind speeds ${\leq}25m\;s^{-1}$.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.21
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• pp.129-151
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• 2003

Nowadays even if environment of international commercial transaction is changing quickly municipal law could not meet with such change accordingly. So far, however, efforts towards unification have prevailingly taken the form of binding instruments, such as non-national or supranational legislation, international conventions or international model laws. Among them, the UNIDROIT Principles with parties' autonomous and yet non-binding character do not only meet the substantive requirements of a true law merchant. In addition they also counter some of the main points of criticism against the modern lex mercatoria. As such the Principles constitute a cornerstone in the lex mercatoria debate and may become the heart of the new lex mercatoria. The purpose of this article is to ask whether there could be applied the Principles in international commerce. For the purpose it is to investigate when the Principles are applied in international commerce and how effectively the Principles are applied for the decision in international commercial disputes. Even though the Principles are used for reference by parties involved for the voluntary regulation of their contract, it is sufficiently expected that the Principles are to be a stepstone of uniform contract law in international commerce. Until now cases of appling the Principles are not satisfied with its expectation as a source of non-legislative means of unification or harmonization of law. Given the party's autonomy in the contract, this is among other things because business parties are strongly tend to observe their national laws in their international commerce. And also, even though there are a number of neutral and uniform regulations for international commercial contracts, parties do not often recognize their usefulness with being up to expectation. In order to explore the applicability of the Principles a number of cases of ICC International Court of Arbitration and others are quoted.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.11
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• pp.1750-1759
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• 2008

The purpose of this study was to comparatively analyze the color characteristics of the Japanese ethnic look advanced by Japanese and western designers in comparison with the actual traditional colors of Japan. The data determining the traditional colors of Japan was collected through a critical apparatus examination of 250 colors and the color data of what determines Japanese ethnic look was collected through an analysis of the clothing appearing in four fashion collections -Paris, Milan, London, and New York- from the 2004 S/S collections to the 2008 F/W collections. For the analysis of these colors, Photoshop was used with an RGB value measuring under 300dpi resolutions. The RGB values were then converted to H V/C values through Munsell Conversion 8.0.3, and they were analyzed using Munsell's 40 Hue and PCCS. The results of this study are as follows: Japanese designers are expressing their own aesthetic theory by designing fashions in traditionally Japanese hues. However, neutral colors and low-chroma tones appear more often than traditional colors. This study illustrates how these designers use color to reflect their inside ideals being oversensitive traditonal ideals. In contrast, western designers reflect more contemporary trends through the use of hues that more clearly reveal their preconception of the colors of the Orient rather than actual traditional Japanese colors. Moreover, these foreign designers tend to approach fashion design by the means of shape rather than color. Japanese designers systematically analyze and apply their own culture to contemporary fashion design. Their efforts serve as a good reference model for research on traditional culture and fashion design.