• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.6
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• pp.27-32
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• 2008

Impulse Radio Ultra Wide Band (IR-UWB) system can be used to wireless position location system because of its unique very short pulse in the order of nanosecond. A few algorithms have been proposed to calculate location of sensors or tags. In this paper, we compare these algorithms and propose 'TDoA with wireless synchronization' as practical solution. Earlier algorithms need special logic to fix the duration to receive and send pulse or assume synchronization with wire. In proposed method, beacons synchronize each other using impulse and nodes can be made simple and cheap. We evaluated the performance and it shows 50% improved accuracy at the error range of 50cm.

• Korean Journal of Adult Nursing
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• v.12 no.3
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• pp.407-417
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• 2000

The purpose of this study was to examine the effect of preoperative teaching as a nursing intervention on the emotional status of the patients prior to surgery. The method of this study was Nonequivalent Control Group Non-Synchronize Design. The data were selected from H universuty hospital in Seoul, and they consisted of an experimental group-30patients, and a control group-30 patients. The questionnaire consisted of 28 Preoperative Stress Inventory(Kang, 1998), and 16 State- Trait Anxiety Inventory(Spielberger, 1972). The collected data were analized by means of frequency, percentage, $X^2$ test, t-test and paired t-test with SPSS WIN. The results of this study were as follows : 1. The level of stress prior to surgery was significantly lower for the preoperative teaching group than for the control group(t=2.61, p< .01). 2. The level of anxiety prior to surgery was not significantly lower for the preoperative teaching group than for the control group. 3. The difference level of the anxiety level the prior to surgery was significantly higher for the preoperative teaching group than for the control group(t=2.82, p< .01). In conclusion, preoperative teaching is a beneficial nursing intervention that has a positive effect on the stress and anxiety of patients prior to surgery. Therefore it is recommended to use the preoperative teaching program as a nursing intervention for patients prior to surgery.

• Journal of Korea Multimedia Society
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• v.13 no.1
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• pp.38-46
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• 2010

A stable game managing system is absolutely needed to accept simultaneous interlacing of many users for on- line game system. The proposed P2P on-line game system in this paper is able to get stable and real-time game managing within limited time stamp utilizing through reorganizing peers according to synchronous time which can be avoid congestion on one region, it is possible to synchronize for game nodes within limited time stamp utilizing. Reorganizing M-tree which leads 10 distribute loads. The system manages each region unit, and it is execute no matter how big game sizes are. Thus to ensure such as the problems of expand server and stabilization or message transmission. Also, prove efficiency of the suggested system through the simulation.

• Journal of Korea Multimedia Society
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• v.9 no.11
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• pp.1410-1420
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• 2006

In this paper, a replica update propagation method for cost optimization of request forwarding in the Grid database is proposed,. In the Grid database, the data is replicated for performance and availability. In the case of data update, update information is forwarded to the neighbor nodes to synchronize with the others replicated data. There are two kinds of update propagation method that are the query based scheme and the log based scheme. And, only one of them is commonly used. But, because of dynamically changing environment through property of update query and processing condition, strategies that using one propagation method increases transmission cost in dynamic environment. In the proposed method, the three classes are defined from two cost models of query and log based scheme. And, cost functions and update propagation method is designed to select optimized update propagation scheme from these three classes. This paper shows a proposed method has an optimized performance through minimum transmission cost in dynamic processing environment.

• Journal of Korea Multimedia Society
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• v.12 no.3
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• pp.345-353
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• 2009

It is for sure that a stable game managing system is absolutely needed to accept simultaneous interfacing of many users for P2P on-line game system. The proposed P2P on-line game system in this paper is able to get smart and stable game managing taking care of extensive players through reorganizing numerous RS(Region Server) and mutual communications among RS's which can be avoid congestion on one region. Moreover, it is possible to synchronize for game nodes in time stamp utilizing Global Zone Buffer of Monitoring Server which leads to breakup loads. The system manages middleware layers in the so-called sub area, and it is able to execute no matter how big the game sizes are. That means, in some ways, we got everything we try to ensure such as the problems of high cost server and stabilization of message transmission. This paper welcomes to prove efficiency of the suggested system through the simulation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.6
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• pp.1167-1173
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• 2005

In this paper, the use of an antenna array is considered for code timing acquisition of DS-CDMA signals. The probabilities of acquisition are evaluated by applying multiple narrow fixed-beams to the conventional MUSIC acquisition approach in the multiuser environment on the time-varying Rayleigh fading channel. Each fixed-beam for spatial filtering is dedicated to an individual angular sector that is formed by dividing the entire angular domain by the number of antenna elements. The fixed-beams with a capability of interference suppression provide the additional degrees of freedom,. Hence, the multibeam-based MUSIC estimator can be used to synchronize to more users than the conventional MUSIC algorithm for one antenna. The multibeam-based subspace method is evaluated to significantly improve the performance of a single antenna based MUSIC technique in multiuser scenarios.

• Journal of Broadcast Engineering
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• v.17 no.4
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• pp.596-610
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• 2012

This paper proposes a method to provide the high quality 3D broadcasting service in a mobile broadcasting system. In this method, audio and video data are delivered through a heterogeneous network, consisting of a mobile network as well as a broadcasting network, due to the limited bandwidth of the broadcasting system. However, it is more difficult to synchronize the left and right video frames of a 3D stereoscopic service, which come through different types of networks. The proposed method suggests the use of the offset from the initial timestamp of RTP (Real Time Protocol) to determine the order of frames and to find the pair of a left and a right frame that must be played at the same time. Additionally, a new signaling method is introduced for a mobile device to request a 3D service and to get the initial RTP timestamp.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.4A
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• pp.365-372
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• 2007

In IEEE 802.11b wireless network, stations synchronize themselves to the beacons periodically sent by the access point(AP) when they are running in low power mode. In case of missing beacon due to noise or traffic from neighboring wireless network stations must be awake until they get the next beacon, which causes energy consumption in stations. In this paper, we propose a scheme searching next beacon consuming little energy. The problems of missing beacon in low power mode of IEEE 802.11b wireless interface are described and a new method to reduce energy consumption is proposed. The proposed method is simulated with the network simulator, ns2, and compared with the low power mode of the IEEE 802.11b. The result measured in terms of station's wakeup time shows some enhancement in energy consumption when some errors occur in receiving frames.

• Development and Reproduction
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• v.17 no.1
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• pp.17-24
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• 2013

This study examined the expression of inhibitor of DNA-binding (Id) proteins and vascular endothelial growth factor (VEGF) in the ovary according to female age using a mice model as the first step in investigating the potential role of Ids and VEGF in ovarian aging. C57BL inbred female mice of three age groups (6-9, 14-16, and 23-26 weeks) were injected with 5 IU pregnant mare's serum gonadotropin (PMSG) in order to synchronize the estrus cycle. After 48 h, ovarian expression of Ids and VEGF was analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR), western blot and immunohistochemistry. Ovarian apoptosis was examined by ovarian expression of Bcl-2 and Bcl-xL. Expression of Id-1 and VEGF was decreased with advancing female age, but not Id-2, Id-3, and Id-4. In particular, their expressions were significantly decreased in aged mice of 23-26 weeks compared with the young mice of 6-9 weeks (p < 0.05). In contrast, ovarian apoptosis was greatly increased in the aged mice compared to the young mice. This result suggests that Id-1 may have an implicated role in ovarian aging by associating with VEGF.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.540-543
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• 2007

The modulation transfer function (MTF) in a camera system is a measurement of how well the system will faithfully reproduce the original scene. The electro-optical camera system consists of optics, an array of pixels, and an electronics which is related to the image signal chain. The system MTF can be cascaded with each element's MTF in the frequency domain. That is to say, the electronics MTF including the detector MTF can be recalculated easily by the acquired system MTF if the well-known test optics is used in the measuring process. A Time-Delay and Integration (TDI) detector can make a signal increase by taking multiple exposures of the same object and adding them. It can be considered the various methods to measure the MTF of the TDI camera system. This paper shows the actual and practical MTF measuring methods for the detector and electronics in the TDI camera. The several methods are described according to the scan direction as well as the TDI stages such as the single line mode and the multiple-lines mode. The measuring is performed in the in the static condition or dynamic condition to get the point spread function (PSF) or the line spread function (LSF). Especially, the dynamic test bench is used to simulate on track velocity to synchronize with TDI read out frequency for the dynamic movement.