• International Journal of Ocean System Engineering
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• v.4 no.1
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• pp.1-18
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• 2014

Heave plates have been widely used to enhance viscous damping and thus reduces the heave response of Spar platforms. Single heave plate attached to the keel of the Spar has been reported in literature (Tao and Cai 2004). The effect of double heave plates on hydrodynamic response in random waves has been investigated in this study. The influence of relative spacing $L_d/D_d$ ($D_d$-the diameter of the heave plate) on the hydrodynamic response in random waves has been simulated in wave basin experiments and numerical model. The experimental investigation has been carried out using 1:100 scale model of Spar with double heave plates in random waves for different relative spacing and varying wave period. The influence of relative spacing between the heave plates on the motion responses of Spar are evaluated and presented. Numerical investigation has been carried out to investigate effect of relative spacing on hydrodynamic characteristics such as heave added mass and hydrodynamic responses. The measured results were compared with those obtained from numerical simulation and found to be in good agreement. Experimental and numerical simulation shows that the damping coefficient and added mass does not increase for relative spacing of 0.4 and the effect greater than relative spacing on significant heave response is insignificant.

• Steel and Composite Structures
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• v.21 no.4
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• pp.921-947
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• 2016

Concrete Filled Fibre Reinforced Polymer Tube (CFFT) for new columns construction has attracted significant research attention in recent years. The CFFT acts as a formwork for new columns and a barrier to corrosion accelerating agents. It significantly increases both the strength capacity (Strength enhancement ratio) and the ductility (Strain enhancement ratio) of reinforced concrete columns. In this study, based on predefined selection criteria, experimental investigation results of 134 circular CFFT columns under axial compression have been compiled and analysed from 599 CFFT specimens available in the literature. It has been observed that actual confinement ratio (expressed as a function of material properties of fibres, diameter of CFFT and compressive strength of concrete) has significant influence on the strength and ductility of circular CFFT columns. Design oriented models have been proposed to compute the strength and strain enhancement ratios of circular CFFT columns. The proposed strength and strain enhancement ratio models have significantly reduced Average Absolute Error (AAE), Mean Square Error (MSE), Relative Standard Error of Estimate (RSEE) and Standard Deviation (SD) as compared to other available strength and strain enhancement ratios of circular CFFT column models. The predictions of the proposed strength and strain enhancement ratio models match well with the experimental strength and strain enhancement ratios investigation results in the compiled database.

• Structural Engineering and Mechanics
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• v.74 no.5
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• pp.611-633
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• 2020

In this paper, a comprehensive review of nanostructures that exhibit piezoelectric behavior on all mechanical, buckling, vibrational, thermal and electrical properties is presented. It is firstly explained vast application of materials with their piezoelectric property and also introduction of other properties. Initially, more application of material which have piezoelectric property is introduced. Zinc oxide (ZnO), boron nitride (BN) and gallium nitride (GaN) respectively, are more application of piezoelectric materials. The nonlocal elasticity theory and piezoelectric constitutive relations are demonstrated to evaluate problems and analyses. Three different approaches consisting of atomistic modeling, continuum modeling and nano-scale continuum modeling in the investigation atomistic simulation of piezoelectric nanostructures are explained. Focusing on piezoelectric behavior, investigation of analyses is performed on fields of surface and small scale effects, buckling, vibration and wave propagation. Different investigations are available in literature focusing on the synthesis, applications and mechanical behaviors of piezoelectric nanostructures. In the study of vibration behavior, researches are studied on fields of linear and nonlinear, longitudinal and transverse, free and forced vibrations. This paper is intended to provide an introduction of the development of the piezoelectric nanostructures. The key issue is a very good understanding of mechanical and electrical behaviors and characteristics of piezoelectric structures to employ in electromechanical systems.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.916-924
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• 2015

Electromagnetic Interference (EMI) is a system to system or environment to system phenomenon. The literature survey proved that the Randomized Pulse Width Modulation (RPWM) technique is a promising technique to reduce EMI. A new Constant Trailing Edge, Randomized Pulse Width Modulation (CTERPWM) technique is proposed in this paper. The effect of the proposed RPWM technique for mitigation of conducted-EMI on Cuk converter operating in Continuous Conduction Mode (CCM) is simulated and tested. In this paper, the analytical expressions for the Power Spectral Density (PSD) are derived for the proposed RPWM technique and are validated by experimental measurements. The effectiveness of the proposed RPWM technique on the mitigation of conducted-EMI is verified comparing simulation and experimental results and it is identified that both the results are almost similar with allowable experimental deviations. The comparative investigation proves that the proposed RPWM technique can mitigate and spread the dominant peaks of conducted-EMI over the complete spectrum for the Cuk converter. Based on the investigation the CTERPWM technique is recommended for adoption.

• Steel and Composite Structures
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• v.22 no.1
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• pp.25-43
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• 2016

This paper presents the results of an experimental study investigating the effects of anchorage systems used in externally bonded steel plates on the strength and ductility of reinforced concrete structures. In the literature, diagonal steel plates bonded to frames were designed to be more flexible than the connections to eliminate the possible effect of the connection flexibility. However, to better evaluate the performance of the strengthened structures, the strength and behavior of connections should also be considered. The purpose of this study was to experimentally investigate the effects of different connection types of steel plates bonded to the frame using anchors on the strengthened RC structures. For this purpose, eleven specimens were designed to simulate the interior and exterior connection behavior. Two of these were used as the control beams and remaining nine for the investigation of the functionality of the end steel plates. Experimental results show that the load carrying capacity of the strengthened beams is directly related to the connection types of the steel plates. For the interior connections, L-shaped end plates that were strengthened using steel anchors must have adequate stiffness to prevent its shape. While, for the exterior connections, the connection with three anchors carried more load than the other exterior connections.

• Ocean Systems Engineering
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• v.8 no.3
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• pp.329-343
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• 2018

The inclination of seabed profile (sloped seabed) is one of the known topographic features which can be observed at different seabed level in the large offshore basin. A mooring system connected between the platform and global seabed is an integral part of the floating structure which tries to keep the floating platform settled in its own position against hostile sea environment. This paper deals with an investigation of the motion responses of an FPSO platform moored on the sloped seabed under the combined action of wave, wind and current loads. A three-dimensional panel discretization method has been used to model the floating body. To introduce the connection of multi-segmented non-linear elastic catenary mooring cables with the sloped seabed, a quasi-static composite catenary model is employed. The model and analysis have been completed by using hydrodynamic diffraction code AQWA. Validation of the numerical model has been successfully carried out with an experimental work published in the latest literature. The analysis procedure in this study has been followed time domain analysis. The study involves an objective oriented investigation on platform motions, in order to identify the effects of the slopped seabed, the action of the wave, wind and current loads and the presence of riser system. In the end, an effective analysis has been performed to identify a stable mooring model in demand of reducing structural responses of the FPSO.

• Journal of Korean Academy of Nursing
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• v.22 no.2
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• pp.185-206
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• 1992

In this study nursing activities were examined to determine the nursing cost. A professional nursing group developed a tool for the investigation. 128 nursing activities were identified by the tool in 16 nursing care areas as referenced in the literature. Each activity was examined for four essential factors to define nursing cost ; time consumed for the care, level of professional skill, degree of independency and performer of the care. The activity was rated by a five point Likert scale. This investigation was conducted with the nursing staffing working in the 21 university hospitals in Korea and having more than four years experience especially in medical or surgical wards. The participating nursing staff were screened on the basic of the recommendation of the nursing director. The data were gathered from June 12th to August 12th, 1989. All the data were analyzed for mean, standard deviation, percent, and correlation coefficients between items. The results are summarized as follows : 1. Direct nursing care was classified into 16 large areas and 128 small activities. 2. No significant correlation was found between the study items of each activity. 3. Among 128 nursing activities, Those performed less than 50% of the time by a nurse were excluded from the nursing cost. Also excluded activities which were given less than 9 marks in all three items, time consumed, level of professional skill, and degree of independency. As a result, 83 activities in 14 nursing care areas were selected for the proposal to estimate nursing cost.

• Journal of the Korean Institute of Rural Architecture
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• v.9 no.3
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• pp.73-82
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• 2007

Ministry of Education and Human Resources presented on December, 2006, 'Alternative school establishment and operation regulation' of contents that can be recognized attainments in scholarship because is authorized if alternative schools fulfill fixed condition. Even though, one time, it was true that several opinions which try to limit to adaptation school of person disqualified for school, thus, various discussion and efforts that specialized school for alternative education does to grow are appearing. However, the expectation which a lot of non authorized schools will apply is not so high because specialized school for alternative education will be controlled in free curriculum and school operation that have been administered and can not be guaranteed school's sell-regulation if acquire legal authorization. Under such social and educational background I surveyed present condition, law, system, literature investigation of existing study, Japanese system and example and authorized two sample specification schools etc. through 'A Basic Study on the Optimum Facilities Criteria Modeling of Regional Specialized Schools for Alternative Education(2006. 10)'. This study was preceded the succession and I visited 17 schools that permit investigation opening of schools among 29 that is authorized until present. So I try to find out architectural planning criteria to activate specialized school for alternative education more through analyzing school's general present condition, establishment idea, operation and specialized education plan, facilities present condition and characteristic.

• The Korea Journal of Herbology
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• v.23 no.1
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• pp.39-44
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• 2008

Objectives : Through surveying the vegetation of woody plants naturally growing in the Chonnam Area. we expect to make good use of the surveyed data for the conservation and utilization of woody plants in the Chonnam Area. And also we hope that we could make a good opportunity to love and conserve the Chonnam Area through this report. Methods : we inspected native and cultivated medicinal woody plants in the Chonnam Area by report and survey, and researched medicinal part through the herbalogy literature. Results : 1. According to the investigation of medicinal woody plant in the Chonnam area, it bears 189 species, 139 genera and 62 families. 2. Rosaceae and Quercus are the biggest share of medicinal woody plants in the Chonnam area. 3. In aspect of medicinal part, roots of 100 species, leaves of 102 species, fruits of 80 species, and barks of 67 species have been using. The leaves part of the most plants are abundantly used. 4. About 30 species of medicinal woody plants are distributed distinctively in Korea. Conclusions : According to the investigation of medicinal woody plant in the Chonnam area, it bears 189 species, 139 genera and 62 families.

• Korean Journal of Human Ecology
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• v.7 no.1
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• pp.69-80
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• 2004

The purpose of this study is to suggest methods for the community design through users' behavior study in apartment housing. This study was approached by using both theoretical investigation and empirical research. The theoretical investigation actualized the concept of community design in apartment housing through a literature survey. The empirical survey focused on seeking out a user-oriented design criteria based on the analysis of residents' usage behavior and mental map. The results of this study are as follow: First. regarding the analysis of the residents' attitude toward the share community space(SCS), it was found that the SCS made a sense as community facilities in apartment housing. Second, regarding the SCS through the metal map, it was shown that the sketch map analysis was a useful research method for the community design by actualizing the residents' behavior characteristics. Third. as to the results of analyzing the metal map, it was found that the considered characteristics in recognition of the SCS were related to the liking with the main paths, cross nodes of the moving line, the location of center. and the complexity. In conclusion, the SCS is the main of community design in apartment housing and the above characteristics in recognition are useful as the guidelines in the SCS planning.