• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.26 no.2
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• pp.113-118
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• 2020

Due to the rapid increase in cyber shopping mall of agricultural products, the parcel delivery service industry also increased, making it necessary to design an optimum packaging for agricultural products. And Due to the recent increase in strawberry consumption, there is also a need for a packaging system for parcel delivery service. In order to establish the criteria for optimum cushioning packaging design of strawberries, the bioyield strength of strawberries by storage time was measured through the ASABE test standards, and the peak acceleration in the resonance frequency and resonance frequency bands of strawberries was measured through the vibration test regulated in the ASTM test specifications. Tray cup pad and corrugated fiberboard box of delivery strawberries were designed using FEM theoretical analysis of contact stress and resonant frequency. In addition, an optimum packaging system was developed with a cushioning and vibration design considering the impact characteristics when distributing agricultural products. Through the performance evaluation and on-site evaluation of the optimum packaging system of strawberries for parcel delivery service, the random PSD test results of the delivery showed a 74% reduction in the acceleration level, and the actual distribution test of the delivery showed that the damage rate of strawberries was not more than 6.7%, indicating that it was possible to use the optimum packaging of strawberries for delivery.

• Journal of the Korean Institute of Gas
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• v.22 no.3
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• pp.65-73
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• 2018

Coalbed methane has a nonlinear desorption curve depending on the pressure, so an appropriate production system should be constructed considering this phenomenon. The capacity and specification of the coalbed methane gas production facility are determined by the gas flow rate and pressure in the coalbed, which is the external boundary condition of the system. Thus, it is essential to analyze these characteristics in gas production. The gas inflow equation was calculated using the reservoir flow model and utilized as the boundary condition of the whole production facility in this study. Also, to understand the effect of pressure drop on the gas flow in the production facility, the nodal analysis was performed using the flow analysis simulator of production equipment, and we determined the proper specifications and operating conditions of the production facility. This study presents a design criteria as to production and gathering system capable of effectively transporting coalbed methane.

• Journal of Korean Society of Steel Construction
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• v.28 no.3
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• pp.203-211
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• 2016

There are no consistent wind load provisions to design the plant tank in Korea. To suggest the appropriate design wind load, five kinds of specifications including KS B 6283, API 650, ASCE 7-10, EN 1991-1-4 are compared. To evaluate the adequacy of wind load specification in each code first, pressure coefficients were calculated in each code and compared with the results of wind tunnel test. Finite element analyses using linear bifurcation analysis were performed with the parameter of h/d and f/d (h : height of cylinderical part of tank, f : roof heigh, d : diameter of tank). By analyzing the results, appropriate wind load criteria which reflects the real wind actions and easy to apply will be suggested.

• Advances in aircraft and spacecraft science
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• v.1 no.2
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• pp.233-251
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• 2014

Each aircraft have to be certified for a specified level of impact energy, for assuring the capability of a safe flight and landing after the impact against a bird at cruise speed. The aim of this research work was to define a scientific and methodological approach to the study of the birdstrike phenomenon against several windshield geometries. A series of numerical simulations have been performed using the explicit finite element solver code LS-Dyna, in order to estimate the windshield-surround structure capability to absorb the bird impact energy, safely and efficiently, according to EASA Certification Specifications 25.631 (2011). The research considers the results obtained about a parametric numerical analysis of a simplified, but realistic, square flat windshield model, as reported in the last work (Grimaldi et al. 2013), where this model was subjected to the impact of a 1.8 kg bird model at 155 m/s to estimate the sensitivity of the target geometry, the impact angle, and the plate curvature on the impact response of the windshield structure. Then on the basis of these results in this paper the topic is focused about the development of a numerical simulation on a complete aircraft windshield-surround model with an innovative configuration. Both simulations have used a FE-SPH coupled approach for the fluid-structure interaction. The main achievement of this research has been the collection of analysis and results obtained on both simplified realistic and complete model analysis, addressed to approach with gained confidence the birdstrike problem. Guidelines for setting up a certification test, together with a design proposal for a test article are an important result of such simulations.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.5
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• pp.535-542
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• 2023

In order to understand the seismic performance of a bridge, it is common to review through seismic performance evaluation and numerical analysis of the target bridge. Seismic performance evaluation and review through numerical analysis are analysis methods for specific target bridges, and many problems can arise in each management body managing bridges nationwide. Therefore, in this study, research was conducted to estimate the seismic performance of public bridges with various types and characteristics. Seismic performance was estimated by applying the seismic risk assessment method, calculating the seismic fragility curve for the type and specifications of the bridge, and estimating the seismic performance of the bridge in use by applying the domestic seismic design standard. In addition, by installing it on the platform, service items were established so that users can easily review the estimation of seismic performance of domestic bridges.

• Journal of the Society of Disaster Information
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• v.8 no.1
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• pp.81-92
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• 2012

In this study, in-depth site investigation related to design and construction of pile foundation was carried out, especially with respect to 103 large-scale bridges located in South Korea. As a result, the depths and location of investigation was unsatisfactory at the foundation investigation process. Moreover, pile load tests were not performed when the capacity of the file is calculated in planning phase, and it was difficult to determine the load capacity limit due to the fact that loading capacity was not specified in pile-loading test. The design criteria related to pile foundation does not reflect the reality of the construction site, and that causes over design, and economic inefficiency in budget. Therefore, the purposes of this study is to review case studies related to the bearing capacity of pile foundations and suggest improvements in the construction specifications.

• Journal of the Earthquake Engineering Society of Korea
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• v.15 no.4
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• pp.33-43
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• 2011

This paper addresses a fundamental study that is necessary to complement and improve the current domestic design specifications for the strong motion duration criterion and the envelope function of artificial accelerograms that can be applied to the earthquake-proof design of nuclear structures. The criteria for the design response spectra and strong motion duration suggested by USNRC and ASCE Standard 4-98 are commonly being used in the profession, and they are first compared with each other and reviewed. By applying 209 real strong earthquake records that are greater than 5 in magnitude at rock sites to the strong motion duration criterion in ASCE 4-98, an empirical regression model that predicts the strong motion duration as a function of the earthquake magnitude was then developed. Using synthetically generated earthquake time histories for the 10 cases whose strong motion durations varied from 6 to 20 seconds, extensive seismic analyses were finally conducted to identify the effects of the strong motion durations on the seismic responses of the nuclear power plant containment structures.

• Explosives and Blasting
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• v.26 no.2
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• pp.1-10
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• 2008

The safe level for residential structures has usually been prescribed as just 'particle velocity' in various specifications in Korea. It implies that there is a possibility of interpreting the 'particle velocity' as the PPV (Peak Particle Velocity), PVS (Peak Vector Sum), or something else, depending on the interpreter. As a result, there have always been some difficulties in both designing a controlled blasting and controling the blast-induced ground vibrations. This paper is intended to show what the role of the safe level criteria such as PPV or PVS is, and also how we should use the concept of the scaled distance equation in a controlled blast design. The paper also emphasizes the importance of the allowable level for various residential structures and its uses in each stage of the controlled blast design.

• Journal of the Korea Concrete Institute
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• v.27 no.6
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• pp.695-703
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• 2015

Acceptance criteria for chemical admixtures of cement concrete were investigated in domestic and international specifications. The reliability was verified for solid content test method of chemical admixture examined statistical analysis by round robin test. The applicability of FT-IR spectroscopy for qualitative measurement of multi-compound chemical admixtures verified. From solid content experimental results, outlier analysed using Cochran, Grubbs and Dickson's Q test. Repeatability and reproducibility standard deviation for solid content results showed 0.25 and 0.098% respectively according to KS A ISO 5725-2 procedure, it can be confirmed reliability of test methods. FT-IR spectrum of liquefied or oven-dried chemical admixtures condition showed big differences. It is needed that the FT-IR analysis is performed on dry material. However there's no difference with the applicability of FT-IR spectroscopy for multi-compound chemical admixtures. So the utility of method analysis could not identify.

• Journal of The Korean Association of Information Education
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• v.13 no.3
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• pp.313-323
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• 2009

The objective of this paper is an implementation of analysing and predicting functions to promote self-directed learning for student's performance assessment system in programming subjects. By adapting Rubric model, the proposed functions inform a student of the assessment criteria and level to be carried out with respects to two-way specifications such as rational ability, problem solving ability and creativity. The proposed system also provides a graphical results of each ability instead of assessment result, for better understanding and analyzing himself/herself based on to the performance assessment and the result. Moreover, the proposed system contains a method to predict future achievement result with moving average technique. Therefore, an academic achievement can be precisely determined by himself/herself to estimate self-directed learning. The teacher can provide different level of educational resources such as supplement learning, problem explains and private instructor etc., in order to maximize efficiency of education.