• Korean Journal of Computational Design and Engineering
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• v.19 no.4
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• pp.324-331
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• 2014

In the design of a combat vehicle, various performances such as firepower, mobility and survivability, etc., should be considered. Furthermore, since these performances relate to each other, design framework which can treat an integrated system should be employed to design the combat vehicle. In this paper, we use empirical interior ballistic and 3D combat vehicle analyses for predicting firepower and mobility performances which are developed in previous study (1) integrated performance modeling. In firepower performance, pitch and roll angle by sequential firing are considered. In mobility performance, vertical acceleration after passing through a bump is regarded. However, since there are many design variables such as mass of vehicle, mass of suspension, spring and damping coefficient of suspension and tire, geometric variables of vehicle, etc., for firepower and mobility performance, we utilize analysis of variance and quality function deployment to reduce the number of design variables. Finally, integrated design optimization is carried out for integrated performance such as firepower and mobility.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.3 s.333
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• pp.1-8
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• 2005

In this paper, we analyzed the DC and RF characteristics of $0.1\;{\mu}m$ metamorphic high electron mobility transistor (MHEMT) using the ISE-TCAD simulation tool. we also analyzed the effects or the scaling on vertical and lateral dimensions such as a gate length, source-drain spacing, and channel thickness. We discussed the degradation of extrinsic transconductance $g_{m,max}$ in the MHEMTs adopting the gate length $(L_g)$ of $sub-0.1\;{\mu}m$. We suggested the model describing the effects on the vertical and lateral parameter scaling.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.97-97
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• 2013

We present a comprehensive study on the integration of h-BN with silicon MOSFET. Temperature dependent mobility modeling is used to discern the effects of top-gate dielectric on carrier transport and identify limiting factors of the system. The result indicates that coulomb scattering and surface roughness scattering are the dominant scattering mechanisms for silicon MOSFETs at relatively low temperature. Interposing a layer of h-BN between $SiO_2$ and Si effectively weakens coulomb scattering by separating carriers in the silicon inversion layer from the charged centers as 2-dimensional h-BN is relatively inert and is expected to be free of dangling bonds or surface charge traps owing to the strong, in-plane, ionic bonding of the planar hexagonal lattice structure, thus leading to a significant improvement in mobility relative to undecorated system. Furthermore, the atomically planar surface of h-BN also suppresses surface roughness scattering in this Si MOSFET system, resulting in a monotonously increasing mobility curve along with gate voltage, which is different from the traditional one with a extremum in a certain voltage. Alternatively, high-k dielectrics can lead to enhanced transport properties through dielectric screening. Modeling indicates that we can achieve even higher mobility by using h-BN decorated $HfO_2$ as gate dielectric in silicon MOSFETs instead of h-BN decorated $SiO_2$.

• Journal of Advanced Navigation Technology
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• v.28 no.4
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• pp.386-392
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• 2024

This paper constructs a precise dynamics model using flightlab, a specialized program for rotor modeling and performance analysis, to simulate urban air mobility (UAM). flightlab is well-suited for detailed modeling of UAM, particularly requiring detailed aerodynamic characteristics under high-altitude and urban wind conditions. The study focuses on implementing and analyzing a lift-cruise UAM model with distributed propulsion using flightlab. The lift-cruise model integrates motors for vertical take-off and fixed-wing flight. Given the limited specific examples of such UAM models in flightlab and challenges in evaluating with conventional fixed-wing or drone models, this research implements and verifies the lift-cruise model using matlab, comparing its performance against flightlab results to validate the modeling approach. This research aims to explore the potential of flightlab for detailed UAM modeling and contribute to technological advancements in future urban transportation.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.3
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• pp.67-79
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• 2003

An efficient mobility management for mobile stations plays an important role in mobile communication networks. Even though many a mobility management schemes have been proposed, most of mobile communication networks adopt the mobility scheme based on zone-based registration. This paper studies the mobility management scheme that combines zone-based registration and 2-step selective paging. We assume cell by cell registration area, not ring by ring registration area of previous studies, and set up a new mobility model based on 2-dimensional random walk model considering the characteristic of zone-based registration to evaluate its performance exactly. We provide numerical results using proposed model to demonstrate the performance of zone-based registration and 2-step selective paging under various circumstances.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.5
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• pp.181-190
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• 2013

PMIPv6(Proxy Mobile IPv6) is a network-based IP mobility management protocol, which can control the mobility without depending on the type of access system or the capability of mobile node. Combining it with SIP mobility, it can establish the route optimization effectively and ensure the terminal mobility and the session mobility. There are many literatures on PMIPv6-SIP in mobility management, but efficient performance analysis and mathematical modeling has not been standardized. For this, a new PMIPv6-SIP architecture is proposed to compare with Pure-SIP in terms of the handover delay and packet loss.

• Construction Engineering and Management
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• v.19 no.2
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• pp.63-68
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• 2018

• Journal of Distribution Science
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• v.18 no.1
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• pp.107-121
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• 2020

Purpose: Shared mobility services are the most notable in the shared economy; however, they have yet to be activated in Korea due to various regulations and conflicts amongst stakeholders. Nevertheless, shared mobility has become an irresistible trend of the times, as it can cause a great deal of economic and environmental benefits. In this vein, the purpose of this study is to contribute to the revitalization of shared mobility services in Korea and to provide service providers with implications for developing consumer-oriented marketing strategies. Research design, data and methodology: Based on the reasons that the users do not use shared mobility service, the factors influencing the behaviors of shared mobility users are structured and analyzed in a reliable, technical and procedural manner. To this end, the theory of reasoned action (TRA) of Ajzen and Fisbbein, the initial trust model (ITM), task technology fit (TTF) and switching cost (SC) are adopted. A total of 202 questionnaires were collected from the respondents who were aware of shared mobility. Then statistical processing of the collected data used SmartPLS(v.3.2.8), a PLS-SEM (Partial Least Squares Structural Equation Modeling) analysis program. The steps of the analysis are as follows. First, a PLS-Algorithm analysis was performed to evaluate the measurement model, and a Bootstraping and Blindfolding analysis was performed to evaluate the structural model and verify the hypotheses. Second, a multi-group analysis (PLS-MGA) was conducted to further analyze the differences depending on whether or not users experienced shared mobility service. Results: The results showed that initial trusts model (ITM) and task technology fit (TTF) have positive effects on users' behaviors through the mediation of the intention to use. As opposed to the assumption, switching costs did not have negative moderating effects in relation to the intention to use and users' behaviors. The influence of IT self-efficacy was significant, depending on the prior experience to use shared mobility services. Conclusions: This study will contribute to the revitalization of domestic shared mobility services and the formulation of service providers' marketing strategies. In future studies, there is a need to explore, reconstruct, and validate factors other than the impact factors of the shared mobility services used in this research model.

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.1
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• pp.11-18
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• 2011

A mobile agent system is the most common software paradigm for distributed applications. A software development model to develop efficiently for these systems is needed. Unified Modeling Language (UML) is a widely used software development model to develop a system for Visualizing, Specifying, Constructing, Documenting. However, UML can not describe in explicit way the necessary mobility of the mobile agent-based software systems. In this paper, the interaction diagrams of UML (sequence diagrams and communication diagrams) are extended and used to express the mobility of the mobile agents in three ways. For a case study, we applied the extended diagrams to a distributed file searching using mobile agents, and showed these diagrams can describe the mobility very well.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.2
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• pp.253-256
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• 2016

In this paper, the power system with electric vehicles is analyzed considering the mobility and diffusion rate of electric vehicles in the smart grid environment. In the previous studies, load modeling and load composition rates have been researched and the results are applied to develop a new load model to explain the mobility of electric vehicles which could affect on the power system status such as power flow and stability. The results would be utilized to research and develop power system analysis methods considering movable charging characteristics of electric vehicles including movable discharging characteristics which could be affected by the diffusion progress of electric vehicles.