• Journal of Korean Academy of Fundamentals of Nursing
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• v.18 no.2
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• pp.160-167
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• 2011

Purpose: The purpose of this study was to identify the effects of an oral stimulation program on premature infant's transition from tube feeding to bottle feeding, decrease in desaturation during feeding, and early discharge. Methods: This quasi-experimental study was performed in one neonatal intensive care unit (NICU) of an university hospital. The control group data (n=69) were obtained from June 2008 to May 2009, and the experimental group data (n=67), from June 2009 to May 2010. The oral stimulation program (OSP) was provided daily before feeding for the experimental group until transition to bottle feeding was completed. Results: The OSP group began bottle feeding earlier and were on complete bottle feeding earlier than control group. Discharge delay due to feeding desaturation was lower than for the control group. Conclusion: The results indicate that OSP for premature infants was helpful in transition from tube feeding to bottle feeding and early discharge and thus can contribute health and development in premature infants.

• Smart Structures and Systems
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• v.10 no.4_5
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• pp.313-329
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• 2012

A challenging issue in design and implementation of an effective structural health monitoring (SHM) system is to determine where a number of sensors are properly installed. In this paper, research on the optimal sensor placement (OSP) is carried out on the Canton Tower (formerly named Guangzhou New Television Tower) of 610 m high. To avoid the intensive computationally-demanding problem caused by tens of thousands of degrees of freedom (DOFs) involved in the dynamic analysis, the three dimension finite element (FE) model of the Canton Tower is first simplified to a system with less DOFs. Considering that the sensors can be physically arranged only in the translational DOFs of the structure, but not in the rotational DOFs, a new method of taking the horizontal DOF as the master DOF and rotational DOF as the slave DOF, and reducing the slave DOF by model reduction is proposed. The reduced model is obtained by IIRS method and compared with the models reduced by Guyan, Kuhar, and IRS methods. Finally, the OSP of the Canton Tower is obtained by a kind of dual-structure coding based generalized genetic algorithm (GGA).

• 한국정보통신설비학회:학술대회논문집
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• 2002.08a
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• pp.208-212
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• 2002

통신기술의 발달에 따라 기존의 통신망은 TP 기반의 NGN 구조로 통합이 추진되고 있으며, 서비스 형태도 음성주도형 서비스에서 음성과 데이터가 혼합된 멀티미디어형 서비스로 전환되는 추세이다. 또한 기존 PSTN 서비스를 인터넷기반으로 대체하는 인터넷전화 서비스가 출현하게 되었다. 인터넷전화 서비스는 VoIP 관련 번호 제도가 체계적으로 도입되고 사업자 역무가 구체화될 경우 본격적인 활성화 단계에 진입할 것으로 예상된다. 기업측면에서는 통신 요금을 절감하고 음성과 데이터를 통합하여 사용할 수 있는 사설망 구축을 적극적으로 도입하거나 활용을 검토하고 있는 추세이며 개인 고객들도 향후 IP 기반의 유무선 인터넷전화 서비스를 많이 활용하게 될 것이다. 결국 ITSP와 사설기업망이 많이 생겨나게 되고, 이러한 환경에서는 ITSP(Internet Telephony Service Provider)와 사설 기업망 가입자들은 모든 타사업자 (ITSP, 무선통신사업자. PSTN 사업자, 사설 기업망 등)들간 통신을 위하여 협약을 체결하고, 호 라우팅을 위한 정보를 유지하고 과금 정산 기능을 지원하여야 하는 문제점이 있다. 이를 위한 방안으로서 사업자간 정산 시스템을 중심으로 ITSP와 사설기업망 가입자를 연동하도록 구성할 수 있다. 프로토콜로서는 ETSI 표준 프로토콜 OSP을 사용하도록 한다. 본 고에서는 사업자간 정산 시스템(OSPs : OSP 서버)을 통한 ITSP와 사설 VoIP 망들간의 호 서비스 연동 방안을 제시하였다.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2007.04a
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• pp.37-47
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• 2007

Factor : Structure Metal pad & SMO size Board level TC test : - Large SMO size better Board level Drop test : - Large SMO size better Factor : Structure Substrate thickness Board level TC test : - Thick substrate better Board level Drop test : - Substrate thickness is not a significant factor for drop test Factor : Material Solder alloy Board level TC test : - Not so big differences over Pb-free solder and NiAu, OSP finish Board level Drop test : - Ni/Au+SAC105, CuOSP+LF35 are better Factor : Material Pad finish Board level TC test : - NiAu/NiAu is best Board livel Drop test : - CuOSP is best Factor : Material Underfill Board level TC test - Several underfills (reworkable) are passed TCG x500 cycles Board level Drop test : - Underfill lots have better performance than non-underfill lots Factor : Process Multiple reflow Board level TC test : - Multiple reflow is not a significant actor for TC test Board level Drop test : N/A Factor : Process Peak temp Board level TC test : - Higher peak temperature is worse than STD Board level Drop test : N/A Factor : Process Stack method Board level TC test : - No big difference between pre-stack and SMT stack Board level Drop test : - Flux dipping is better than paste dipping but failure rate is more faster

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.5
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• pp.381-389
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• 2014

This study is concerned with the estimation of vibration-field of a cylindrical structure by modal expansion method(MEM). MEM is a technique that identifies modal participation factors using some of vibration signals and natural modes of the structure: The selection of sensor locations has a big influence on predicted vibration results. Therefore, this paper deals with four optimal sensor placement( OSP) methods, EFI, EFI-DPR, EVP, AutoMAC, for the estimation of vibration field. It also finds optimal sensor locations of the cylindrical structure by each OSP method and then performs MEMs. Predicted vibration results compared with reference ones obtained by forced response analysis. The standard deviations of errors between reference and predicted results were also calculated. It is utilized to select the most suitable OSP method for estimation of vibration field of the cylindrical structure.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.2
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• pp.25-30
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• 2018

Sn-Pb solder has been used in automotive electronics for decades. However, recently, due to the environmental and health concerns, some international environmental organizations such as the end-of-life vehicle (ELV) enacted legislation banning of the Pb usage in automotive electronics. For this reason, many studies to develop and promote Pb-free soldering have been significantly reported. Meanwhile, because of flexibility and lightweight, flexible printed circuit boards (FPCBs) have been increasingly used in automotive electronics for lightweight to improve fuel efficiency and space utilization. Although the properties of lead-free solders for automotive electronics have been widely studied, there is a lack of research on the reliability performance of the lead-free solder joint on FPCB under user conditions. This study reported the properties of solder joints between Pb-free solders such as Sn3.0Ag0.5Cu, Sn0.7Cu and Sn0.5Cu0.01Al (Si), and various FPCBs finished with organic solderability preservative (OSP) and electroless nickel immersion gold (ENIG). To evaluate on joint properties and reliabilities with different solder compositions and surface-finishing materials, pull strength test, thermal shock test, and bending cycle test were performed and analyzed. After the bending cycle test of solder joint on OSP-finishing, the fractures were occurred in solder and the lifetime of Sn3.0Ag0.5Cu solder joint was the longest.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.4
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• pp.79-85
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• 2007

This study was focused on the feasibility of ultrasonic bonding of Au stud flip chip bumps on the flexible printed circuit board (FPCB) with three different surface finishes: organic solderability preservative (OSP), electroplated Au and electroless Ni/immersion Au (ENIG). The Au stud flip chip bumps were successfully bonded to the bonding pads of the FPCBs, irrespective of surface finish. The bonding time strongly affected the joint integrity. The shear force increased with increasing bonding time, but the 'bridge' problem between bumps occurred at a bonding time over 2 s. The optimum condition was the ultrasonic bonding on the OSP-finished FPCB for 0.5 s.

• Broadcasting and Media Magazine
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• v.18 no.1
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• pp.44-54
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• 2013

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.289-292
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• 2007

FTTH (Fiber to the Home) is constructed with optical devices and optical cables from central office (CO) to subscribers. With FTTH, it is possible to provide service platform in order to meet the customers' emerging demands for more bandwidth/security and diverse IP multimedia applications including high definition (HD) video streaming service. FTTH can provide enough bandwidth from 100Mbps to several Gbps per subscriber. It is also most appropriate network architecture for convergence of communication and broadcasting. So, FTTH is thought the final destination of telecom operators, since it is the fastest and most reliable solution so far and various IP multimedia services are possible through it. In this paper, newly attempted technologies of FTTH construction for apartment complexes using CWDM-PON system are discussed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.3
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• pp.241-247
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• 2011

Although intensive development continues on innovative sensor systems, there is still considerable uncertainty in deciding on the number of sensors required and their locations in order to obtain adequate information on structural behavior. This paper is concerned with the sensor locations on a beam-structure for prognostic structural health monitoring. The purpose of this study is to investigate how to determine optimal sensor placement(OSP) from the sensitivity information of a known failure mode. The sensitivity of the forced vibration response of a beam to the variation of stiffness due to a crack is calculated analytically and used to determine the optimal sensor locations for the specified failure mode. The results of this method compared with the results of different OSP methods. The results have shown that the proposed method on optimal sensor placement is very effective in structural health monitoring.