• Journal of the Society of Naval Architects of Korea
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• v.53 no.1
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• pp.29-36
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• 2016

In shipbuilding and offshore plant construction, pipe-stools of various types are installed. Moreover, these are many quantities but they must be installed in a successive manner. Due to these characteristics the pipe-stool installation processes easily tends to cause the schedule delays in the overall production processes. In order to reduce delay, the goal of this study is to predicts production’s lead time before manufacturing. Through this predictions it’s expected to reduce total production’s lead time by improving it's process. First of all, we made MLR(Multiple Linear Regression) and PLSR(Partial Least Square Regression) model to predict pipe-spool's lead time and then compared predictability of MLR and PLSR model. If a explanatory variable is added, it will be possible to predict results precisely.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.4
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• pp.904-921
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• 2014

The main objective of this paper is to propose a new Finite Element (FE) model updating technique for damped beam structures. The present method consists of a FE model updating, a Degree of Freedom (DOF) reduction method and a damping matrix identification method. In order to accomplish the goal of this study, first, a sensitivity-based FE model updating method using the natural frequencies and the zero frequencies is introduced. Second, an Iterated Improved Reduced System (IIRS) technique is employed to reduce the number of DOF of FE model. Third, a damping matrix is estimated using modal damping ratios identified by a curve-fitting method and modified matrices which are obtained through the model updating and the DOF reduction. The proposed FE model updating method is verified using a real cantilever beam attached damping material on one side. The updated result shows that the proposed method can lead to accurate model updating of damped structures.

• International Journal of Ocean System Engineering
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• v.1 no.3
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• pp.171-179
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• 2011

This paper presents the concept design procedure of a floating-type combined renewable energy platform based on hydrodynamic analyses and is focused on the fatigue design of taut-type mooring lines of the platform. Two types of combined renewable energy platforms are considered: a combination of wind turbine, wave turbine and photovoltaic energy plant and a combination of wind turbine, current turbine and photovoltaic energy plant. The basic configurations are conceptually determined from the understanding of floating offshore plants, while the main dimensions have been determined based on a hydrostatic calculation. Fully coupled hydrodynamic analyses have been carried out to identify the motion characteristics of the floating body and the tension histories of the mooring lines. The tension history is used for the fatigue life prediction based on the rain-flow cycle counting method. For the fatigue life prediction, tension life curves from API and the Palmgren-Miner rule are employed.

• Journal of the Korean Institute of Landscape Architecture
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• v.34 no.1 s.114
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• pp.1-9
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• 2006

The purposes of this study are to develop the concept and the measurement method of IGS(Index of Greenness in Streetscape) and to analyze the present condition of street environments through field surveys of IGS in Seoul. IGS is a new index which directly expresses human's perceptions of plants in a street and defined as the area ratio of which leaves of plants occupy in an eye-level view of a person standing on the center line of a street. In practice, IGS can be calculated from a photograph taken from a center point of a street at about 1.5 meter height from the ground with single lens reflex camera equiped with 50mm standard lens. The photograph must have a special composition in a way that the center point of the photograph is positioning at the visual vanishing point of street center line. Then the IGS can be calculated by computing the percentage of the area covered with the plant leaves in the photograph. Types of streets in Seoul were classified according to road functions into 4 types. We performed field surveys and calculated IGSs from 300 sample sites in Seoul. Followings summarize some of study results. The average IGSs for arterial roads, highways, alleys and back streets are 16.91%, 16.33%, 13.97% and 7.50% respectively. The difference of average IGS values between Ginkgo biloba and Platanus occidentalis was relatively large. From observation IGSs from April 4th, 2003 to October 2nd, 2003, it was evident that the range and timing of each plant species' IGS change is not the same. According to questionnaire to public officials taking charge of street greening, the current evaluated IGS is 24.4%, and it is expected to be 40.7% in the future.

• Advances in aircraft and spacecraft science
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• v.7 no.5
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• pp.459-473
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• 2020

The aircraft nose landing gear (NLG) can suffer of an unstable vibration called shimmy that is responsible of discomfort and of fatigue stress on the gear strut components. An adaptive controller is proposed in this paper to cope with the aforementioned problem. It is based on a method called Modified Simple Adaptive control (MSAC) which is able of governing the NLG motion by using a feedback signal that relies on just one output of the plant. The MSAC only asks for the passivity of the controlled plant. With this aim, a parallel feedforward compensator is employed in this work to let the system satisfies the almost strictly passivity (ASP) requirements. The nonlinear equations that govern the aircraft NLG shimmy vibration behavior are used to analyzed the controlled system transient response undergoing an initial disturbance and taking into account different taxiing speed values.

• Journal of the Korean Institute of Landscape Architecture
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• v.19 no.2
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• pp.52-64
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• 1991

The actual vegetation and environmental impact grade of Daekwanrim in Hamyang were investigated and the structure of the plant community was analyzed by the classification of TWINSPAN and three kinds of multivariate ordination (PCA, RA, DCA) techniques.Twenty-eight plots were set up by the clumped sampling method in June of 1990. Carpinus laxiflora and C. tschonoskii communities covered 38% and Quercus species communities covered 39% of the total rea. Environmental impact class 3 and 4 area. Twenty-eight plots were divided into three groups according to the degree of damage by TWINSPAN and ordination techniques. The dominant species in the shrub layer of the heavily damaged site and the light damaged site were Styrax japonica and Sasamorpha purporanscens, so the sucessional trends should be disturbed. As a result of the analysis for the relationship between the stand scores of DCA and the environmental impact class, they had a tendancy to increase from the light damaged to heavily damaged site.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.3
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• pp.86-96
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• 2003

This study aims to improve system for the enlargement of artificial planting spaces through grasp several problems about it and related system in domestic and foreign. In order to improve system for the extension of artificial planting spaces in the urban area following plans have been presented. First, it is necessary to launch various bonus, subsidies and incentives for making planting spaces in the urban area. Second, subdivision of related regulations for using diverse planting methods is needed. Third, government has to take the initiative in pushing on with planting of artificial spaces. Fourth, it is necessary to development of concrete techniques. Finally, it is desirable to plant artificial spaces which animal and plant can live, low effect to environment and material can be circulated although the value of plantation as a meaning of simple green also are admitted. Planting of artificial spaces should be introduced in a positive light for conservation and restoration of urban ecosystem.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.2
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• pp.97-107
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• 2000

This study aims to develop the model of evaluation on greenspace to increase the sustain ability of the planning and management for site-scale development projects. The results of this study can be summarized as follows: (1) The comprehensive principles of sustainable development projects were established, which include coexistence of man and nature, reflection of ecological principles, minimization of environmental pollution and damage, recycling and reuse of materials. (2) According to established principles, the evaluation criteria were classified into seven categories as follows: retention of ample greenspace, formation of greenspace as a habitat, species diversity of vegetation, consideration of indigenous plants, construction of green network, conservation of greenspace, and reuse of plant materials. (3) As a result of the analysis of questionnaire of experts, evaluation model was worked out with which we can evaluate environmental friendliness greenspace. And, the final evaluation indicators for greenspace are the rate of greeneries volume, securing habitat, indigenous plants, reuse of plant materials, and species diversity of vegetation, and the indicator of greenspace conservation.

• Journal of the Korean Society of Systems Engineering
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• v.12 no.2
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• pp.69-80
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• 2016

The purpose of this study is to establish a component reutilization system in Nuclear Power Plant (NPP) by Object-Oriented Systems Engineering Method (OOSEM). Unified Modeling Language (UML) is mainly used for OOSEM. Operational Concept (OpsCon), Use cases, Structure Diagrams, and Behavior Diagrams are developed to analyze stakeholders needs, system requirements, logical architecture, and physical architecture. Based on the current decommissioning and purchasing system of the component, some activities from their systems were excepted and additional new activities were developed for a component reutilization system.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.2
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• pp.269-282
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• 1998

The visual preference of interiors focusing on lobbies was investigated as a function of six predictor variable on the base of the Informational Approach: complexity, coherence, mystery, spaciousness, brightness, plant. The Common Fcator Analysis of preference ratings yielded six common factors which helped to account for 22.3 percent of the variance in preference response to the scene. Among these factors, the factor defined as 'bright with many plants' was the most preferred and the factor defined as 'simple and closed' was the least preferred. The environmental attributes reflected in six groups of scenes were colour, resting place, window and the six predictors. In the commercial building scenes, complexity, spaciousness, coherence, brightness and mystery out of six predictors accounted for 74 percent of preference variance as the significant contributors. In the business building scenes, three predictors which are brightness, complexity, spaciousness accounted for 84 percent of preference variance. 'The amount of plant' not only influenced the preference indirectly through the intervening variable, complexity, but also was moderately correlated with brightness. The overall pattern of the resulted confirmed the usefulness of the Informational Approach to predict the preference in interiors focusing on lobbies.