• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.4
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• pp.275-287
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• 2008

Noise externalities are a ubiquitous problem in modern societies. Research to estimate damages and potential efficient solutions therefore is important for addressing such problems. The results of a hedonic property model show that noise has a statistically significant and quantitatively important negative effect on property values. The key results for the best model show that damages (in year 2000 dollars) are - $5000 ${\ast}$ (ln dB), where dB is noise measured in decibels, allowing for the influence of other factors. Because ln(dB) is a strictly concave funaion, the "noise damage function"exhibits diminishing marginal effects with noise.

• Journal of Digital Contents Society
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• v.9 no.4
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• pp.669-677
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• 2008

Since the great success of the Disney animations like , the classification of audience target in animation according to an age group started a possibility of edutainment in the industry. Especially, a few animations for preschool children made by Korea have been largely successful in domestic and foreign markets. The study analyzed a distinguished structure of a story stressed by character by Greimas's theories in the educational animation. The animation for kids as this study target is one of successful contents in edutainment. It also analyzed as one of parallel contents in abroad. It is a meaningful study which considers a story structure of the animation as aspects of edutainment contents for preschool children.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.2
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• pp.467-478
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• 1994

This paper deals with dynamic behaviors of a free-piston Vuilleumier heat pump system, which are characterized by stroke of each diplacer/stroke ratio, operating frequency and phase angle. Based on the Isothermal Model, basic equations of motion are derived and linearized. In particular, dependence of damping coefficients of the dynamic parameters are taken into account in the formulation, which does not bring additional difficulties in the analysis. In order to investigate effects of design conditions on the dynamic parameters are taken into account in the formulation, which does not bring additional difficulties in the analysis. In order to investigate effects of design conditions on the dynamic characteristics, calculations are performed for the prototype made by Schulz and Thomas and results are qualitatively compared with their data obtained from the analysis as well as the experiment. It appears that they made a mistake in evaluating the hysteresis loss of the gas spring in their analysis. And, the present results show a better agreement with their experimental data than those by their own analysis. Although there are some unresolved aspects such as frequency variations with respect to the mean pressure and the hot space temperature, it is expected that the present analysis may be an effective tool for prediction of dynamics of a free- pistion VM machine at the preliminary design stage.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.8
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• pp.613-621
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• 2009

Coal is the energy resource which is important with the new remarking energy resource. Coal combustion produces more NOx per unit of energy than any other major combustion technology. Pollutant emission associated with coal combustion will have a huge impact on the environment. Coal conversion has three processes which are drying, coal devolatilization and char oxidation. Coal devolatilization process is important because it has been shown that HCN which is converted from volatile N contributes 60 to 80% of the total NOx produced. This paper addresses mass release behavior of char, tar, gas and HCN in an experiment of Laminar Flow Reactor with two coals such as Roto middle coal (Sub-bituminous) and Anglo coal (Bituminous). The experiment is compared with the data predicted by CPD model for mass release of HCN about Roto south, Indominco, Weris creek and China orch coals. The results show that HCN increases as a function of decreasing the ratio of fixed carbon(FC)/ volatile matter(VM of the coals contain.)

• Water for future
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• v.7 no.1
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• pp.71-77
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• 1974

This paper reviews several different single site generation models for further development of a model for generating the Synthetic sequences of streamflow in the continuous streams like main streams in Korea. Initially the historical time series is looked using a time series technique, that is correlograms, to determine whether a lag one Markov model will satisfactorily represent the historical data. The single site models which were examined include an empirical model using the historical probability distribution of the random component, the linear autoregressive model(Markov model, or Thomas-Fiering model) using both logarithms of the data and Matala's log-normal transformation equations, and finally gamma distribution model.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.5
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• pp.391-401
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• 2009

The hybrid approach for structural experiments decomposes a structure into independent substructures that can be tested or simulated. The results from the decomposed substructures are combined to predict the behaviors of the entires structure. The hybrid approach is especially useful for the hybrid pseudo-dynamic tests that overcome the limitations of size of a test structure present in a shaking table test. The development of a computer system for the hybrid experiment requires a data model that formally organizes the information involved in the hybrid experiments. This paper provides the data model for representing the information involved in the hybrid experiments, by modifying the classes and attributes for the hybrid experiments in the Lehigh Model that is one of the data models for structural experiments. The data model for the hybrid experiments includes the classes for the physical substructures being tested and the analytical substructures being analyzed, and the simulation coordinator managing the overall experiments. Some objects for classes are implemented as an example to show the links among the classes. The data model presented in this paper can be applied for developing a computer system that helps structural engineers and researchers store, share, and access the information for the hybrid experiments.

• Journal of the Korea Concrete Institute
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• v.21 no.5
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• pp.599-609
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• 2009

This paper discusses generalized modeling schemes for both reinforced concrete (RC) and post-tensioned (PT) flat plate buildings. In this modeling approach, nonlinear behavior due to slab flexure, moment and shear transfer at slab-column connections, and punching shear was included along with linear secant stiffness of each member or connection that accounts for concrete cracking. This generalized model was capable of simulating all different scenarios of slab-column connection failures such as brittle punching, flexure-shear interactive failure, and flexural failure followed by drift-induced punching. Furthermore, automatic detection of drift-induced punching shear and subsequent backbone curve modifications were realistically modelled by incorporating the limit state model, in which gravity shear versus drift capacity relations were adopted. The validation of the model was conducted using one-third scale two-story by two-bay RC and PT flat plate frames. The comparisons revealed that the model was robust and effective.

• Fire Science and Engineering
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• v.18 no.1
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• pp.54-66
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• 2004

In this article, we are to suggest the hazard-assessing method for the underground pipelines, and find out the pipeline-maintenance schemes of high efficiency in cost. Three kinds of methods are applied in order to refer to the approaching methods of listing the hazards for the underground pipelines: the first is RBI(Risk Based Inspection), which firstly assess the effect of the neighboring population, the dimension, thickness of pipe, and working time. It enables us to estimate quantitatively the risk exposure. The second is the scoring system which is based on the environmental factors of the buried pipelines. Last we quantify the frequency of the releases using the present THOMAS' theory. In this work, as a result of assessing the hazard of it using SPC scheme, the hazard score related to how the gas pipelines erodes indicate the numbers from 30 to 70, which means that the assessing criteria define well the relative hazards of actual pipelines. Therefore. even if one pipeline region is relatively low score, it can have the high frequency of leakage due to its longer length. The acceptable limit of the release frequency of pipeline shows 2.50E-2 to 1.00E-l/yr, from which we must take the appropriate actions to have the consequence to be less than the acceptable region. The prediction of total frequency using regression analysis shows the limit operating time of pipeline is the range of 11 to 13 years, which is well consistent with that of the actual pipeline. Concludingly, the hazard-listing scheme suggested in this research will be very effectively applied to maintaining the underground pipelines.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.167.2-167.2
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• 2012

경희대학교와 UC Berkeley, Imperial College London에서 공동으로 진행하는 TRIO-CINEMA Mission(TRiplet Ionosphere Observatory-Cubesat for Ion, Neutral, Electron and MAgnetic fields)은 총 3기의 초소형 위성으로 구성되어 있다. 3기의 위성은 고도 650~800km 상공의 태양동주기 궤도운동을 예상하고 있으며, 지구 근접공간의 입자 검출과 자기장 측정의 과학 임무를 맡게 된다. TRIO-CINEMA 비행 모델(Flight Model)의 환경시험은 진동시험과 열진공시험으로 진행되었다. 진동시험은 X, Y, Z 세 축에 대해 Sine 과 Random 모드로 진행되었다. TRIO-CINEMA가 탑재 될 러시아의 드네프르 로켓의 요구사항은 각 축에서 20Hz 이상의 고유진동수, Sine의 경우 최대 0.8G와 4oct/min Sweep Rate, Random의 경우 5.2Grms 와 35초의 지속시간에서의 안정성을 만족하는 것이다. 시험 결과 TRIO-CINEMA가 요구사항을 모두 만족시키는 것을 확인하였다. 또한, 열 주기 시험(Thermal Cycling Test)을 진행하여 우주공간에서 위성 시스템이 정상 동작하는지에 대한 신뢰성을 검증하였다. 열주기 시험은 미국 MIL표준 값을 참고하여 $10^{-6}Torr$에서 $-20{\sim}30^{\circ}C$의 온도를 주었으며, 시험을 진행하는 동안과 시험 후에 위성이 정상작동 함을 확인하였다. 이에 본 연구의 시험 방법과 그 결과를 기술하였다.

• Water for future
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• v.18 no.3
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• pp.253-264
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• 1985

Basically, there are two ways viewing the reservoir storage-yield relationship., The most common viewpoint is the determination of the storage required at a given reservoir to supply a required yield. This type of problem is usually encountered in the planning and early design phases of a reservoir. The second viewpoint is the determination of yield from a given amount of storage. This often occurs in the final design phases or in re-evaluation of an existing reservoir for a more comprehensive analysis. The purpose of this study is to improve the present methodology estimating the storage-yield relationship for a reservoir design or a reservoir operation. The Residual Mass curve Technique, the slightly modified version of Low Flow Techniques and the Transition Probability Matrix Technique are reviewed and examined for the best fit technique to find the reservoir storage-yield realtionship. The historical data during 1917~1940 at the proposed Hongchun damsite and the synthetic data simulated by Thomas-Fiering model are utilized to examine the reservoir storge-yield relationship with three techniques in detail. After the three techniques which estimate the reservoir storage-yield relationship were reviewed extensively, it was concluded that the Residual Mass Curve Technique and the slightly modified version of Low Flow Techniques were suitable for a preliminary design, but the Transition Probability Matrix Technique Provided satisfactory results as a final design technique because it reflected the variation of a monthly yield as well as seasonlly.