• The KIPS Transactions:PartC
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• v.9C no.2
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• pp.257-266
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• 2002

In 3GPP2 wireless data communications, Mobile IP is used to support macro mobility and PDSN performs the function of foreign agent. The mobility supported when a mobile station moves from one PDSN to another is called a macro mobility. In this Paper, we first examine the possibilities of packet loss and change of packet sequences that can be occurred in macro mobility. Then, to resolve such Problems, we suggest a seamless handoff algorithm in PDSNs based on packet sequence control for each of down-stream and up-stream cases respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.428-429
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• 2006

In this thesis, verifies electrical-optical characteristics of phosphorescent materials. basic structure of fabricating devices is glass/ITO/$\alpha$-NPD($300{\AA}$)/CBP:Guest($300{\AA}$)/BCP($80{\AA}$)/$Alq_3(100{\AA})$/Al($1000{\AA}$). In efficiency, fabrication of organic light emitting diodes using $Ir(btp)_2acac$ phosphorescent material is external quantum efficiency 0.268% as doping concentration 3%. At CIE coordinates, phosphorescent material $Ir(btp)_2acac$ following materials moves high purity red color(x=0.6686, y=0.3243). The brightness shows $285cd/cm^2$.

• Journal of Magnetics
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• v.18 no.3
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• pp.321-325
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• 2013

The problem of mixed convection in a differentially heated lid-driven square cavity filled with Cu-water nanofluid under effect of a magnetic field is investigated numerically. The left and right walls of the cavity are kept at temperatures of $T_h$ and $T_c$ respectively while the horizontal walls are adiabatic. The top wall of the cavity moves in own plane from left to right. The effects of some pertinent parameters such as Richardson number (ranging from 0.1 to 10), the volume fraction of the nanoparticles (ranging 0 to 0.1) and the Hartmann number (ranging from 0 to 60) on the fluid flow and temperature fields and the rate of heat transfer in the cavity are investigated. It must be noted that in all calculations the Prandtl number of water as the pure fluid is kept at 6.8, while the Grashof number is considered fixed at 104. The obtained results show that the rate of heat transfer increases with an increase of the Reynolds number, while but it decreases with increase in the Hartmann number. Moreover it is found that based the Richardson and Hartmann numbers by increase in volume fraction of the nanoparticles the rate of heat transfer can be enhanced or deteriorated compared to the based fluid.

• International Journal of Advanced Culture Technology
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• v.9 no.3
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• pp.327-333
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• 2021

Inbody is a tool for measuring health information with high reliability and accuracy to analyze body composition. Unlike the existing method of storing/processing and outputting data on the server side, the health information generated by InBody requires accurate support for health sharing and data analysis services using mobile devices. However, in the process of transmitting body composition measurement information to a mobile service, a problem may occur in data transmission/reception processing. The reason for this is that, since the network network in the cloud environment is used, if the connection is cut off or the connection is changed, it is necessary to provide a global service, not a temporary area, focusing on the mobility of InBody information. In addition, since InBody information is transmitted to mobile devices, a standard schema should be defined in the mobile cloud environment to enable information transfer between standardized InBody data and mobile devices. We propose a mobile cloud system using EMRA(Extended Metadata Registry Access) in which a mobile device processes and transmits body data generated in the inbody and manages the data of each local organization with a standard schema. The proposed system processes the data generated in InBody and converts it into a standard schema using EMRA so that standardized data can be transmitted. In addition, even when the mobile device moves through the area, the coordinator subsystem is in charge of providing access services. In addition, EMRA is applied to the collision problem due to schema heterogeneity occurring in the process of accessing data generated in InBody.

• Journal of Convergence for Information Technology
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• v.9 no.3
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• pp.30-35
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• 2019

An unattended recording system based on smartphone based image image tracking is rapidly developing. Among the existing products, a system that automatically tracks and rotates the object to be photographed using an infrared signal is very expensive for general users. Therefore, this paper proposes a mobile unattended recording system that enables automatic recording by anyone who uses a smartphone. The system consists of a commercial mobile camera, a servomotor that moves the camera from side to side, a microcontroller to control the motor, and a commercial wireless Bluetooth Earset for video audio input. In this paper, we designed a system that enables unattended recording through image tracking using smartphone.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.67-71
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• 2019

In this paper, we derive a reference error probability performance in the environment where mobile satellite terminal is operated. When the satellite terminal moves, shadowing occurs due to the surrounding obstacles and the BER is lowered. We use the Lutz model simulating the environment in which mobile satellite terminals operate The Lutz model combines the Rician distribution with the Suzuki model. The error probability is derived from the numerical analysis of two distribution functions. The simulated results using the measured results in the Korean Peninsula forest area were similar to the BER results obtained using the Lutz model. Intuitively, the approximated results are similar to the measured results. Numerically, the BER error is about 3e-4 or less at an SNR of 30dB.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.3
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• pp.99-110
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• 2021

This study aims to examine empirically the industry and economic fundamental factors that affect the stock prices of the leading palm oil company in Indonesia. The dynamics of stock price are analyzed using the autoregressive distribution lag (ARDL) model both for symmetric and asymmetric effects. The data used in this study are monthly data for the period from 2008:01 to 2020:03. In the long run, the company stock price moves in line with the competitor company stock price at the current time. The palm oil price has a positive effect on the stock price. Meanwhile, inflation negatively affects the stock price in the short run. The estimated equilibrium correction coefficient indicates a reasonably quick correction of the distortion of the stock price equilibrium in monthly dynamics. However, fundamental factors have asymmetric effects, especially the response of stock price when these factors decrease rather than increase in the short run. Stock prices that are responsive to declines in fundamental performance should be of particular concern to both investors and management in their strategic decision making. The results of this study will contribute to the enrichment of literature related to stock prices from the viewpoint of economic analysis on firm-level data.

• Journal of the Korean Society of Visualization
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• v.18 no.3
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• pp.116-121
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• 2020

In this study, a single-phase analysis of droplet slug with different contact angles was performed based on the visualization of experimental results. Droplet slug - flowing between gases in a hydrophobic mini channel - moves with a triple contact line without a gas liquid film on the wall. The results show that the rotational flow inside the droplet occurred; this was compared and verified with the results of two-phase analysis. The pressure field shows pressure rise at the front and rear ends. The effective length - the section that satisfies the laminar flow condition - became shorter as the droplet velocity increased. The Choi's correlation for the effective length agrees with this analysis results with a slight difference. This difference is judged as the difference in the contact angle of the slug model.

• Biomedical Science Letters
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• v.27 no.4
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• pp.239-247
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• 2021

The scuttle fly is a fly species in the Phoridae family. Scuttle fly which moves abruptly after standing for a while and stop suddenly to rush off again. These characteristic behaviors of the scuttle fly seem to be related to muscular and nervous system or neurotransmitters. Thus, we focused at the neurotransmitter, corazonin (Crz) that is known to be related to resistance to stress and investigated the developmental process of the neurons in the scuttle fly. In a previous studies, we found that there are three groups of corazoninergic neurons in the larval CNS of the scuttle. Larva has 3 pairs of Crz neurons at the dorsolateral area of the brain, 1 pair at the dorsomedial brain and 8 pairs at the ventral nerve cord. In this studies, among these neurons, 1 pair of dorsomedial brain and 8 pairs of ventral nerve cord disappear in early pupal stage after metamorphosis. Only the 3 pairs of dorsolateral brain persist expression of Crz gene through all the period of pupa stage. This group of neurons converge gradually to frontal center of the brain and situated at the medial region. These pairs of corazoninergic neurons keep their number and location in adult stage. In the future, we expect further studies on the histological characteristics of corazonin-expressing cells and the expression of corazonin gene.

• Tribology and Lubricants
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• v.38 no.6
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• pp.281-286
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• 2022

In this study, the effects of Elasto-hydrodynamic lubrication pressure on the critical shoulder height of raceway in an angular contact ball bearing were investigated. Both 3D contact analyses using an influence function and the EHL analysis were conducted for the contact geometry between the ball and raceways. The pressure distributions by 3D contact analysis and EHL analysis for an example bearing were compared. The effect of ellipse truncation on the minimum film thickness also investigated from EHL analysis. The critical shoulder height in the dry contact and the EHL state were compared for various applied loads. It is shown that when the ellipse truncation occurs, the pressure spike for the EHL conjunction is higher than that for the dry contact, and its location moves more inward of the contact center. The steep pressure gradients would increase the flow rate, so in order to maintain flow continuity a significant reduction in film thickness and an abrupt rise in pressure occurs in the edge of shoulder. Significant reduction of the minimum film thickness occurs near the edge of shoulder. The critical shoulder heights in the EHL state are calculated as higher values compared with in the dry contact. This results shows that the determination of critical shoulder height by the EHL analysis is more proper.