• Journal of KSNVE
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• v.10 no.3
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• pp.474-479
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• 2000

Piston slap is not only one of the major sources of noise and vibration in internal combustion engines but also a cause of the deterioration of engine performance. The basic mechanism associated with the piston slap seems to be quite simple but the phenomenon is in fact complicated with regard to many mechanical elements associated, First of all the impact force of piston slap must be identified to estimate engine block surface vibration, In this paper model of collision point is proposed to calculate the impact force when slap surface vibration. In this paper model of collision point is proposed to calculate the impact force when slap occurs. The parameters of the model are estimated by employing the concept of point mobility, . The predicted and experimentally observed vibration results confirm that the proposed method is practically useful.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.5-8
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• 2001

This paper describes the development of SiC MOSFET model for high temperature applications. The temperature dependence of the threshold voltage and mobility of SiC MOSFET is quite different from that of silicon MOSFET. We developed the empirical temperature model of threshold voltage and mobility of SiC MOSFET and implemented into HSPICE. Using this model the MOSFET Id-Vds characteristics as a function of temperature are simillated. Also the SiC CMOS operational amplifieris designed using this model and the temperature dependence of the frequency response, transfer characteristics and slew rate as a function of temperature are analyzed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.6
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• pp.83-89
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• 2012

In this paper, the new user mobility management scheme which can be utilized to register user's location for interworking with heterogeneous overlay convergent networks under the time-varying radio propagation environment has been proposed. Thus the user mobility management can be considered in order to model and to evaluate the behaviors of users in the overlay convergent networks. This mobility management scheme will be very useful in characterizing the user mobility behaviors and can be used to estimate the signaling traffic and frequency spectrum demands for massive data transfer for the heterogeneous overlay convergent networks.

• Asia pacific journal of information systems
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• v.24 no.2
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• pp.115-140
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• 2014

In a dynamic business environment, the enterprise mobility solution for a mobile office (EMS) has been adopted to increase the competitive edge of organizations. By using an EMS, performance is expected to be enhanced. However, the related literature has paid little interest to the impact of system quality in an EMS on the information quality produced by the system. On the basis of socio-technical theory, we posited that the system quality in an EMS influences information quality. In addition, we investigated the relationships between the above two qualities, use and job performance by considering task mobility and task inter-dependence as control variables. Survey respondents were from many industries using EMSs. The result of structural equation modeling shows that system quality positively affects information quality, and other relationships in the model are proven statistically significant. We also found that system quality has stronger impacts on use and job performance than information quality does in EMS. However, system quality does not affect use in case both task mobility and task inter-dependence exist. The theoretical and practical implications of the result are discussed in the paper.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.3
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• pp.486-489
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• 2021

Recently, the demand for the use of personal mobility vehicles, such as an electric kickboard, is increasing explosively because of its high portability and usability. However, the number of traffic accidents caused by personal mobility vehicles has also increased rapidly in recent years. To address the issues regarding the driver's safety, we propose a novel approach that can monitor context information around personal mobility vehicles using deep learning-based object detection and smartphone captured videos. In the proposed framework, a smartphone is attached to a personal mobility device and a front or rear view is recorded to detect an approaching object that may affect the driver's safety. Through the detection results using YOLOv5 model, we report the preliminary results and validated the feasibility of the proposed approach.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.4
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• pp.13-28
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• 2009

Routing protocols in Delay/Disruption Tolerant Networks(DTN) are important to enhance the performance of transmission delay and delivery success ratio. In this paper, we propose an efficient DTN routing algorithm, called "Nobility Pattern based Routing(MPR)", that controls the total number of transferred message copies based on mobility patterns of mobile nodes. We consider a realistic "Levy walk" mobility pattern that has a super-diffusive property which well represents human mobility pattern. We implemented a DTN simulator using ONE simulator for the proposed MPR algorithm and Levy walk mobility pattern. Simulation results show that mobility patterns are very important for accurate evaluation of DTN routing performance, and the proposed MPR enhances the routing performance of delivery delay and success delivery ratio under realistic mobility pattern.

• International Journal of Oral Biology
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• v.42 no.4
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• pp.175-181
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• 2017

The aim of this study was to provide a basis for the molecular mechanism underlying the pharmacological action of ethanol. We studied the effects of 1-propanol on the location of n-(9-anthroyloxy)palmitic acid or stearic acid (n-AS) within the phospholipids of synaptosomal plasma membrane vesicles (SPMV). The SPMV were isolated from the bovine cerebral cortex and liposomes of total lipids (SPMVTL) and phospholipids (SPMVPL). 1-Propanol increased the rotational mobility of inner hydrocarbons, while decreasing the mobility of membrane interface, in native and model membranes. The degree of rotational mobility varied with the number of carbon atoms at positions 16, 12, 9, 6 and 2 in the aliphatic chain of phospholipids in the neuronal and model membranes. The sensitivity of increasing or decreasing rotational mobility of hydrocarbon interior or surface by 1-propanol varied with the neuronal and model membranes in the following order: SPMV, SPMVPL and SPMVTL.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.8
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• pp.321-328
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• 2014

In this paper, we present a MapReduce-based mobility pattern mining system which can predict efficiently the next place of mobile users. It learns the mobility pattern model of each user, represented by Hidden Markov Models(HMM), from a large-scale trajectory dataset, and then predicts the next place for the user to visit by applying the learned models to the current trajectory. Our system consists of two parts: the back-end part, in which the mobility pattern models are learned for individual users, and the front-end part, where the next place for a certain user to visit is predicted based on the mobility pattern models. While the back-end part comprises of three distinct MapReduce modules for POI extraction, trajectory transformation, and mobility pattern model learning, the front-end part has two different modules for candidate route generation and next place prediction. Map and reduce functions of each module in our system were designed to utilize the underlying Hadoop infrastructure enough to maximize the parallel processing. We performed experiments to evaluate the performance of the proposed system by using a large-scale open benchmark dataset, GeoLife, and then could make sure of high performance of our system as results of the experiments.

• IEMEK Journal of Embedded Systems and Applications
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• v.13 no.2
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• pp.83-91
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• 2018

With the development of IT (Information Technology) technology, embedded system and network technology are combined and used in various environments such as military environment as well as everyday life. In this paper, we propose a new airdropped distributed mobility model (ADMM) modeling the dispersion falling of the direct shot of a cluster bomb, and we compare and analyze some representative MANET routing protocols in ADMM in ns-3 simulator. As a result of the analysis, we show OLSR routing protocol is promising in ADMM environment in the view points of packet delivery ratio (PDR), end to end delay, and jitter. In addition, we propose a new adaptation scheme for OLSR, AND-OLSR (Average Node Distance based adaptive-OLSR) to improve the original OLSR in ADMM environment. The new protocol calculates the average node distance, adapts the period of the control message based on the average node distance increasing rate. Through the simulation study, we show that the proposed AND-OLSR outperforms the original OLSR in PDR and control message overhead.

• Journal of Korea Multimedia Society
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• v.15 no.12
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• pp.1492-1498
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• 2012

One of the major issues in current internet architecture is that it was not designed to support the user mobility. In order to overcome this restriction, in this paper, we propose an identifier/locator separation architecture which contain the overlay mapping system to store the identifier-to-locator mapping record. In addition, we design the mobility management scheme base on Identifier/Locator separation above for Furture Internet architecture. We then devise the analysis model to evaluate the signaling cost of our scheme. By conducting the simulation. we show that our scheme can operate with lower signaling cost than other schemes.