• Journal of the Korea Society for Simulation
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• v.27 no.2
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• pp.61-69
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• 2018

As the technology of information and communication has developed over recent years, an embedded system is applied in multiple industries and becomes more complicated. For this reason, embedded system development cost and time are also increased. For decreasing the cost and time, this paper suggests requirement evaluation method for concurrent development of an embedded system based on Discrete Event System(DEVS) Formalism. This paper proposes a method of describing the requirements specification in the form of DEVS atomic model. Also, the paper proposes the evaluator model that compares evaluation target system and the requirements model that is an implementation of requirement specification and proposes the evaluation method using them. In addition, we propose a method to utilize the requirement model created for requirements evaluation in the concurrent development process of the embedded system. As the case study, this paper proceeds requirement evaluation of Kinect depth data processing system.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.5
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• pp.11-20
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• 2014

Due to the importance of vehicle detector which plays an essential role in generating real-life traffic information, maintaining detector data quality is preeminent in advanced traffic management and information systems (ATMIS). To this end, agencies periodically conduct performance tests on detectors. Detector evaluation is generally performed by comparing baseline data with corresponding detector data. Here, two important things need to be addressed; one is errors (or uncertainties) included in baseline data and the other is the confidence interval concept to represent evaluation results of sample data to corresponding ones of population. To resolve these problems, a new detector evaluation scheme is introduced and the scheme is applied to individual level detector evaluations of loop, video image, and radar detectors. The purpose of individual level evaluation is to eliminate the balancing (or cancelling-out) effects of over- and under-counts. As a consequence, the proposed scheme is proven to be effectively applied to real-world detector evaluations.

• Journal of the Korean Society for Railway
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• v.20 no.4
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• pp.539-549
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• 2017

This paper proposes an analytical methodology of station capacity calculation on high - speed railway. Our method explicitly takes into account the effect of the number of sidings and the combination of train halting patterns (stop - stop, pass - stop, stop - pass, pass - pass) on the capacity of a station. To verify the reliability of our model, we conducted capacity analysis of selected stations using the Railsys simulator. We found that the difference in calculated capacity between our model and Railsys was less than 10%. After Monte Carlo simulation, our model was determined to be a good one. In addition, the consistency in capacity between our model and the train-path allocation program (Korea Rail Network Authority) was statistically significant.

• Journal of the Korea Convergence Society
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• v.10 no.2
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• pp.217-225
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• 2019

The Latent Growth Modeling(LGM) is known as the typical analysis method of longitudinal data and it could be classified into unconditional model and conditional model. It is common to assume that the growth trajectory of unconditional model of LGM is linear. In the case of quasi-linear, the methodology for improving the model fitness using Sequential Pattern of Association Rule Mining is suggested. To do this, we divide longitudinal data into quintiles and extract periodic changes of the longitudinal data in each quintiles and make sequential pattern based on this periodic changes. To evaluate the effectiveness, the LGM module in SPSS AMOS was used and the dataset of the Youth Panel from 2001 to 2006 of Korea Employment Information Service. Our methodology was able to increase the fitness of the model compared to the simple linear growth trajectory.

• Journal of the Korean Institute of Gas
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• v.1 no.1
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• pp.73-80
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• 1997

This study was performed to develop the dispersion modeling methodology for quantitative prediction of the hazard distance or toxic buffer distance by comparing 10-min average, 30-min average, and 1-hr average maximum ground-level concentration with $Cl_2$ regultaion concentration, IDLH and ERPG-3 concentration for hazardous toxic gas, $Cl_2$ releases from the storage tank of the chemical plant facilities. For this dispersion modeling, the source term model, dispersion model, meteorological and topographical data are incorporated into the SuperChems model, and then the effects of the atmospheric stability, wind speed, and surface roughness length changes on the maxum ground-level concentration were estimated.

• Environmental and Resource Economics Review
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• v.23 no.3
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• pp.435-451
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• 2014

This paper attempts to evaluate an environmental regulation program which enforces installation of filtering equipment to reduce major air pollutants from used diesel vehicles. A real option model is presented to incorporate fuel cost uncertainty and irreversibility of emission-reducing investment. A finite-life option based on finite difference method is developed to consider the limited life expectancy of used vehicles. After taking into account social benefits from emission reduction and costs from decreasing fuel efficiency after the adoption of filtering technology, the result finds overall positive performance of the Pollution Reduction Program. However, the result suggests that the Program be designed to be more specific to vehicle types to improve program performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.1006-1015
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• 1998

In general, attenuation at frequencies over 20GHz is mainly due to absorption by satmospheric gases, rain, and snow. Among this factors rain become an important limiting factor. Rain attenuation is highly influenced by rainfall-intensity and it varies over time and space. Thus it is requeired to obtain spatial and temporal data of rainfall-intensity for precise prediction of rainfall attenuation. In this paper, rainfall intensity of thiry-two measurement sites in South Korea excluding JeiJdo Islands over recent ten years is obtained and the regional relation between rainfall-intensity and percent of time is analyzed. Also we present the new method about rainfall-intensity cumulative distribution.

• Journal of Korean Society of Transportation
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• v.21 no.2
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• pp.119-130
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• 2003

SP data have been widely used in assessing new transport policies and transport related plans. However, one of criticisms of using SP is that respondents may show different reaction between hypothetical experiments and real life. In order to overcome the problem, combination of SP and RP data has been suggested and the combined methods have been being developed. The purpose of this paper is to suggest a new SP and RP combined method using error component method and to verify the method. The error component method decomposes IID extreme value error into non-IID error component(s) and an IID error component. The method estimates both of component parameters and utility parameters in order to obtain relative variance of SP data and RP data. The artificial SP and RP data was created by using simulation and used for the analysis, and the estimation results of the error component method were compared with those of existing SP and RP combined methods. The results show that regardless of data size, the parameters of the error component method models are similar to those assumed parameters much more than those of the existing SP and RP combined models, indicating usefulness of the error component method. Also the values of time for error component method are more similar to those assumed values than those of the existing combined models. Therefore, we can conclude that the error component method is useful in combining SP and RP data and more efficient than the existing methods.

• The Journal of the Korea Contents Association
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• v.21 no.8
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• pp.442-454
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• 2021

Many domestic and international airlines that experienced dramatic recession due to COVID-19 pandemic are carefully being ready to normalise operations as a number of governments has begun to vaccinate for COVID-19. So with the same market share from domestic to short distant international services, the competition between Full Service Carriers (FSC) and low cost carriers (LCC) is anticipated to be more intensive. To explore the concepts such as the perception, value, attitude and faith of the object, this study implements Q methodology proposed to complement the limitations of quantitative and qualitative research methodology. As a result, the consumers of airlines' brand are divided into three types - the type of utility seeking, value-oriented and task-related. Using Q samples which consist of 25 statements, this study specifically approached the traits of each type by observing the subjectivity with the comparative P sample group that is made up for 20 participants. By discovering the type of FSC and LCC's brand asset and comparing the recognition of consumers, not only does this study evoke the need for a strategic direction of the effective management of Airlines' Brand asset but also have a signification in the way that especially provide hypotheses for follow up studies.

• Journal of Navigation and Port Research
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• v.28 no.3
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• pp.177-184
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• 2004

The purpose of this study is to identify and evaluate the competitiveness of container ports in ASEAN(Association of Southeast Asian Nations) and Korea, which plays a leading role in basing the hub of international logistics strategies at the onset of the 21st century. Its ultimate purpose is to consider the relevant policy-making by comparing the competitiveness of ASEAN and Korea's container ports. This paper adopted the HFP method, which is an empirical analysis that evaluated the port competitiveness by quantifying it a, a qualitative attribute in the aforementioned area, where both ASEAN and Korea vie with each other for increasing container throughput. The results of this study showed that Singapore ranked the first in the subject of study in view of the competitiveness, followed by Busan(2) and Manila(2) as a leading group of the relevant ports in international logistics strategies. This analytic evaluation contributes to the empirical approach applied to policy-making by the HFP method, which is the newest research technique in social science through the comparative study of port competitiveness between ASEAN and Korea.