• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.274-276
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• 2004

싱크의 이동성은 대규모 센서 네트워킹에 새로운 도전을 야기한다. 이동 싱크의 위치는 센서필드 전역에 걸쳐 전달되어야 하며, 이를 위해 각 센서노드는 새로운 정보를 갱신해야 한다. 그러나 빈번한 위치 갱신은 파워의 제약을 가진 센서에는 초과 에너지 낭비를 일으키고, 무선 통신의 충돌도 증가시킬 것이다. 이에 따라 본 논문은 다중 이동 싱크와 소스가 확장가능하면서 효율적으로 데이터를 전달하는 방법을 제안한다. 각 데이터 소스와 모바일 싱크가 적극적으로 싱크가 이벤트 정보를 획득 가능하도록 그리드 구조를 형성하고, 질의를 보내려는 하는 싱크도 로컬로 질의를 전송함으로써 그리드 형성에 적극 참여하였다. 본 제안 방법은 소스와 싱크가 중간 경유 노드에서 위치 정보를 교환함으로써 낮은 오버헤드로 경로 설정이 가능하게 하였다.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.49-58
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• 2014

A low-swing differential near-ground signaling (NGS) transceiver for low-power high-speed mobile I/O interface is presented. The proposed transmitter adopts an on-chip regulated programmable-swing voltage-mode driver and a pre-driver with asymmetric rising/falling time. The proposed receiver utilizes a new multiple gain-path differential amplifier with feed-forward capacitors that boost high-frequency gain. Also, the receiver incorporates a new adaptive bias generator to compensate the input common-mode variation due to the variable output swing of the transmitter and to minimize the current mismatch of the receiver's input stage amplifier. The use of the new simple and effective impedance matching techniques applied in the transmitter and receiver results in good signal integrity and high power efficiency. The proposed transceiver designed in a 65-nm CMOS technology achieves a data rate of 13 Gbps/channel and 0.3 pJ/bit (= 0.3 mW/Gbps) high power efficiency over a 10 cm FR4 printed circuit board.

• The Journal of the Acoustical Society of Korea
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• v.37 no.4
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• pp.248-255
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• 2018

It is known that the road noise on the rear seat of a hatchback type car is worse than that of a sedan type car because of the weakness on sealing structure. Therefore, a sound sealing system and sufficient absorption/insulation performance are required. In the case of a compact segment car, however, the application of the sufficient absorption and insulation materials is limited, because of the restriction on the production cost and weight of the car. In this study, we estimate the noise transmission path on the vehicle's body structure from tires and ground using the PBNR (Power Based Noise Reduction) method which is useful in quantitative measurement. Based on these results, we suggest an alternative absorption/insulation method for the better performance of rear seat road noise reduction in a compact hatchback car.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.7
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• pp.76-81
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• 2011

A new via cutting structure in 2-layer DRAM package substrate has been fabricated to lower its power distribution network(PDN) impedance. In new structure, part of the via is cut off vertically and its remaining part is designed to connect directly with the bonding pad on the package substrate. These via structure and substrate design not only provide high routing density but also improve the PDN impedance by shortening effectively the path from bonding pad to VSSQ plane. An additional process is not necessary to fabricate the via cutting structure because its structure is completed at the same time during a process of window area formation. Also, burr occurrence is minimized by filling the via-hole inside with a solder resist. 3-dimensional electromagnetic field simulation and S-parameter measurement are carried out in order to validate the effects of via cutting structure and VDDQ/VSSQ placement on the PDN impedance. New DRAM package substrate has a superior PDN impedance with a wide frequency range. This result shows that via cutting structure and power/ground placement are effective in reducing the PDN impedance.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.4
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• pp.61-68
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• 2023

In this study, Sn-3.5Ag-15.0Fe composite solder was manufactured and applied to TLP bonding to change the entire joint into a Sn-Fe IMC(intermetallic compound), thereby applying it as a high-temperature solder. The FeSn₂ IMC formed during the bonding process has a high melting point of 513℃, so it can be stably applied to power modules for power semiconductors where the temperature rises up to 280℃ during use. As a result of applying ENIG surface treatment to both the chip and substrate, a multi-layer IMC structure of Ni₃Sn₄/FeSn₂/Ni₃Sn₄ was formed at the joint. During the shear test, the fracture path showed that cracks developed at the Ni₃Sn₄/FeSn₂ interface and then propagated into FeSn₂. After 2hours of the TLP joining process, a shear strength of over 30 MPa was obtained, and in particular, there was no decrease in strength at all even in a shear test at 200℃. The results of this study can be expected to lead to materials and processes that can be applied to power modules for electric vehicles, which are being actively researched recently.

• Journal of Arbitration Studies
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• v.30 no.2
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• pp.165-184
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• 2020

In this study, the factors affecting opportunism in the relationship between suppliers and key accounts were analyzed from the viewpoint of transaction cost theory, market power theory, and relationship marketing theory. As a result of the hypothesis test, Hypothesis 1 stating that demand volatility will have a positive effect on opportunism and Hypothesis 2 that transaction-specific investment will have a positive effect on opportunism were also supported. In addition, Hypothesis 3 stating that channel power will have a positive effect on opportunism was also supported. Lastly, Hypothesis 4 stating that relational commitment will have a negative effect on opportunism was not supported, along with Hypothesis 5 stating that transaction satisfaction will have a negative effect on opportunism. The theoretical and practical implications of this study are as follows. This study has identified the antecedents of opportunism by comprehensively applying the transaction cost theory, market power theory, and relationship marketing theory. In addition, this study can identify what a company should manage specifically to lower opportunism by identifying the antecedents of opportunism. The limitations of this study and the directions for future studies are as follows. First, not all of the antecedents of opportunism of key accounts have been extensively investigated from the viewpoint of the transaction cost theory, market power theory, and relationship marketing theory. In the future, it is necessary to identify additional factors. Second, the study was conducted only in the supplier's viewpoint. In future studies, it is expected that more accurate research results can be obtained by simultaneously examining not only the supplier's point of view but also the buyer's point of view.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.6
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• pp.117-122
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• 2017

Cabin noise due to the electric powertrain of electrical vehicle may consists of motor noise caused by electrical mismatch and gear noise coming from reduction gearbox. These sound may be considered rather small noise compared to those of internal combustion engine, but without masking effect, the noise can be more annoying for customer. Thus, this paper demonstrates the characteristics of electrical vehicle powertrain noise, and the effect of passive damping material for the noise reduction. The typical motor noise can be affected by the motor torque. Also, it is demonstrated that the reduction gearbox may be a weak point for the noise path compared to the motor housing. With vehicle test, it is shown that the damping patch is more effective for noise reduction with deceleration condition than with acceleration condition.

• The KIPS Transactions:PartA
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• v.13A no.1 s.98
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• pp.1-10
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• 2006

For efficient searching in unstructured peer-to-peer systems, random walk was proposed and several replication methods have been studied to compensate for the random walk's low query success rate. This paper proposes an efficient replication scheme that improves the accuracy and speed of queries and reduces the cost by minimizing the number of replicas and by utilizing caches. In this scheme, hub nodes store only content's caches, and one of their neighbors stores the replica. By determining hubs with only limited and local information, we can adaptively generate caches and replicas in dynamic peer-to-peer networks.

• Journal of Advanced Navigation Technology
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• v.7 no.2
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• pp.191-198
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• 2003

In this paper, we analyze the performance of transmit diversity techniques which are the key technologies of the third generation mobile communication systems. Transmit diversity techniques adopted on the specification of 3GPP are classified into open-loop and closed-loop methods depending on the existence of feedback data. In WCDMA systems, the DPCH signal is space-time coded to provide a mobile station with diversity. Computer simulations shall be performed to analyze and compare their performance considering the effect of mobile speed, number of path, power control, and delay of feedback with the WCDMA slot format #13 for application to WCDMA systems.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.2
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• pp.9-18
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• 1999

In this paper, large capacity Photonic ATM switch structure is proposed. It contains mixed routing structure using TDM and WDM methods. Through this structure, we can get not only required hardware reduction, and optical power loss reduction in cell routing procedure but also the less complexity of electrical parts using passive device. Also, it is designed for ease to simplicity of extension in throughput, so it is suitable structure for large capacity Photonic ATM switching system of the future.