• Journal of the Korean Society for Railway
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• v.17 no.2
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• pp.140-147
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• 2014

Line planning is an important step to determine the optimal frequencies of trains given the forecasted demand for each train type. The main input data for line planning is the leg traffic demand which can be derived using suitable traffic assignment models. However most assignment models require a line plan, in other words, train frequencies or headways, so that inconsistent results just by the procedural approach to find an optimal line plan after determining leg traffic can be avoided. This paper suggests a unified model that can consider the traffic assignment and line planning, simultaneously. We further provide an elaborated approximation algorithm and, finally, provide experimental results determined for the Korean railway network.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.10
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• pp.295-302
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• 2020

The study examines an empirical case that explores the key constructs of the Unified Theory of Acceptance and Use of Technology (UTAUT) (Venkatesh, Morris, Davis & Davis, 2003) and the relationship between security and privacy of the Theory of Perceived Risk (TPR) (Bauer, 1960). This study employs survey data of 200 young Internet users aged 18 to 25. The study was conducted through two steps: preliminary research by qualitative research method to form the official research scale then formal research by quantitative research method using CFA and SEM to test the research model. The research results show that performance expectancy and social influence significantly predict behavioral intention to use e-wallets in payment. In contrast, the factors, namely, security and privacy, and effort expectancy, are statistically insignificant on behavioral intention. Nevertheless, the facilitating conditions factor still affects the behavior of using e-wallets. The study proposes a model to generalize the online payment environment through the integration of UTAUT and TPR models that are important for online payment management and researchers in the technology environment. The findings of this study suggest that social influence significantly affects the intention of young people to use e-wallets instead of security and privacy.

• Journal of the Korea Computer Industry Society
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• v.6 no.3
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• pp.529-538
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• 2005

AUML (Agent Unified Modeling Language) is specification anger of agent software system, sight anger, language that do creation by purpose. Do so that may apply Together that is one of automation application program creation system to Agent's BDI in trend sophistication of software, large size Tuesday in this research and investigate this about operation between component system. Standard detailed statement (FIPA:Foundation for Inteligent Physical Agent) that use can consist by data exchange between component and cooperate each other even if type of component is different mutually to base ACL message, and protocole use and study about method and accuracy and consistency that minimize error when embody this using meta model base etc.. through object intention modelling.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.2
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• pp.683-701
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• 2012

IEEE 802.11 standard has achieved huge success in the past decade and is still under development to provide higher physical data rate and better quality of service (QoS). An important problem for the development and optimization of IEEE 802.11 networks is the modeling of the MAC layer channel access protocol. Although there are already many theoretic analysis for the 802.11 MAC protocol in the literature, most of the models focus on the saturated traffic and assume infinite buffer at the MAC layer. In this paper we develop a unified analytical model for IEEE 802.11 MAC protocol in ad hoc networks. The impacts of channel access parameters, traffic rate and buffer size at the MAC layer are modeled with the assistance of a generalized Markov chain and an M/G/1/K queue model. The performance of throughput, packet delivery delay and dropping probability can be achieved. Extensive simulations show the analytical model is highly accurate. From the analytical model it is shown that for practical buffer configuration (e.g. buffer size larger than one), we can maximize the total throughput and reduce the packet blocking probability (due to limited buffer size) and the average queuing delay to zero by effectively controlling the offered load. The average MAC layer service delay as well as its standard deviation, is also much lower than that in saturated conditions and has an upper bound. It is also observed that the optimal load is very close to the maximum achievable throughput regardless of the number of stations or buffer size. Moreover, the model is scalable for performance analysis of 802.11e in unsaturated conditions and 802.11 ad hoc networks with heterogenous traffic flows.

• Korean Journal of Computational Design and Engineering
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• v.1 no.1
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• pp.20-32
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• 1996

The boundary evaluation technique for Boolean operation on non-manifold models which is regarded as the most popular and powerful method to create and modify 3-D CAD models has been developed. This technique adopted the concept of Merge and Selection in which the CSG tree for Boolean operation can be edited quickly and easily. In this method, the merged set which contains complete information about primitive models involved is created by merging primitives one by one, then the alive entities are selected following the given CSG tree. This technique can support the hybrid representation of B-rep(Boundary Representation) and CSG(Constructive Solid Geometry) tree in a unified non-manifold model data structure, and expected to be used as a basic method for many modeling problems such as data representation of form features, and the interference between them, and data representation of conceptual models in design process, etc.

• Structural Engineering and Mechanics
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• v.41 no.4
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• pp.495-508
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• 2012

The strength theory of concrete is significant to structure design and nonlinear finite element analysis of concrete structures because concrete utilized in engineering is usually subject to the action of multi-axial stress. Experimental results have revealed that lightweight aggregate (LWA) concrete exhibits plastic flow plateau under high compressive stress and most of the lightweight aggregates are crushed at this stage. For the purpose of safety, therefore, in the practical application the strength of LWA concrete at the plastic flow plateau stage should be regarded as the ultimate strength under multi-axial compressive stress state. With consideration of the strength criterion, the ultimate strength surface of LWA concrete under multi-axial stress intersects with the hydrostatic stress axis at two different points, which is completely different from that of the normal weight concrete as that the ultimate strength surface is open-ended. As a result, the strength criteria aimed at normal weight concrete do not fit LWA concrete. In the present paper, a multi-axial strength criterion for LWA concrete is proposed based on the Unified Twin-Shear Strength (UTSS) theory developed by Prof Yu (Yu et al. 1992), which takes into account the above strength characteristics of LWA under high compressive stress level. In this strength criterion model, the tensile and compressive meridians as well as the ultimate strength envelopes in deviatoric plane under different hydrostatic stress are established just in terms of a few characteristic stress states, i.e., the uniaxial tensile strength $f_t$, the uniaxial compressive strength $f_c$, and the equibiaxial compressive $f_{bc}$. The developed model was confirmed to agree well with experimental data under different stress ratios of LWA concrete.

• Atmosphere
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• v.21 no.4
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• pp.497-506
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• 2011

Korean mid- and upper-level aviation turbulence guidance (KTG) system is developed using the unified model (UM)-based regional data assimilation and prediction system (RDAPS) of the Korea Meteorological Administration. The KTG system includes three steps. First, the KTG system calculates a suite of diagnostics in the UM-RDAPS domain. Second, component diagnostics that have different units and numerical magnitudes are normalized into the values between 0 and 1, according to their own thresholds in the KTG system. Finally, normalized diagnostics are combined into one KTG predictor by measuring the weighting scores based on the probability of detection, which is calculated using the observed pilot reports (PIREPs) exclusively of moderate-or-greater (MOG) and null (NIL) intensities. To investigate the optimal performance of the KTG system, two types (RD-KTG and UM-KTG) of the KTG systems are developed and evaluated using the PIREPs over Korea and East Asia. Component diagnostics and their thresholds in the RD-KTG are founded on the 8-yrs (2002.12-2010.11) MM5-based RDAPS (previous version of the RDAPS; ${\Delta}x$ = 30 km) and PIREPs data, while those in the UM-KTG are based on the 6 months (2010.12-2011.5) UM-based RDAPS (${\Delta}x$ = 12 km) and PIREPs data. In comparison between the RD-KTG and UM-KTG, overall performance of the UM-KTG (0.815) is better than that of the RD-KTG (0.79) during the recent 6 months, because forecasting skill for the upper-level wind is higher in the UM-RDAPS than in the MM5-RDAPS. It is also found that the UM-KTG is more efficient than the RD-KTG according to the statistical evaluations and sensitivity tests to the number of component diagnostics.

• Journal of Information Technology Services
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• v.22 no.1
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• pp.29-42
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• 2023

Amid the global movement to harness individual data and boost the data economy, MyData services that utilize personal data are being implemented in earnest in the financial sector in Korea due to the government's active encouragement policy. To this end, MyData service providers must have a service system for business operators that collects and efficiently loads personal information scattered in various financial institutions with individual consent, and comprehensively analyzes and provides it. The system must not only have strict security management capabilities, but also be built in a flexible form that takes into account future data scalability and additional services. In this paper, it has been proposed to be implemented the essential functions that MyData service system must have and the core functions that can manage the entire data life cycle from data collection, distribution to disposal in the form of a platform. In addition, the strengths of the platform structure were reviewed, and the effectiveness of the platform model was examined upon application.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.26 no.2
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• pp.108-115
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• 2018

This study was undertaken to explore the determinants affecting behavioral intention to adopt airport self-service. Based on the theoretical model incorporating the Unified Theory of Acceptance and Use of Technology (UTAUT) and the Technology Acceptance Model (TAM), in this study, a revised and extended model was proposed in order to better explain Airport Self-service adoption. Moreover, the aim was to determine the mediating effect of hedonic motivation on Airport Self-service adoption. The proposed model was empirically tested using survey data provided by 323 respondents and was analyzed using a multiple regression analysis.

• Journal of the Earthquake Engineering Society of Korea
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• v.21 no.1
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• pp.59-67
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• 2017

Due to a lack of the hoop action of lateral reinforcements the effective confining force in rectangular sections reduces compared to circular ones. Therefore, the stress-strain model obtained from the experimental data with circular sections overestimates the lateral confinement effect in rectangular sections, which evaluates seismic safety margin of overall structural system excessively. In this study experiments with laterally-confined square sections have been performed and the characteristic values composing stress-strain model have been analyzed. With introduction of section coefficients, in addition, the new unified stress-strain model applicable to square sections as well as circular ones has been proposed.