• ETRI Journal
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• 제25권1호
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• pp.9-18
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• 2003

We mathematically analyze the passband vestigial sideband (VSB) system for the Advanced Television Systems Committee (ATSC) digital television standard and present a baseband-equivalent VSB model. The obtained baseband VSB model is represented by convolution of the transmission signal (before modulation) and the baseband equivalent of the complex VSB channel. Due to the operation of the physical channel as an RF passband and the asymmetrical property of VSB modulation, it is necessary to use a complex model. However, the passband channel may be reduced to an equivalent baseband. We show how to apply standard channel model information such as delay, gain, and phase for multiple signal paths to compute both the channel frequency response with a given carrier frequency and the resulting demodulated impulse response. Simulation results illustrate that the baseband VSB model is equivalent to the passband VSB model.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2570-2575
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• 2003

Monitoring a power transmission line is significant for power electric companies. In this paper, we propose a new method for detecting an fault point of power transmission line by use of M-sequence correlation technique. In this method, detecting signal is used as one or plural M-sequences ( same characteristic polynomial, including normal and reverse mark, synchronized ). In receiving point, we make same sequence with the input one and take crosscorrelation function between M-sequence and the received signal. We can see transfer fanctions of plural paths between inputs and a output taps separated from different of delay times on the crosscorrelation function, and from these transfer fanctions, so we compare them when fault occurred with in usual.

• Journal of Mechanical Science and Technology
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• 제18권11호
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• pp.1909-1915
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• 2004

The hermetic rotary compressor is one of the most important components of an air conditioning system since it has a great effect on both the performance and the noise and vibration of the system. Noise and vibration occurs due to gas pulsation during the compression process and to unbalanced dynamic force. In order to reduce noise and vibration, it is necessary to identify their sources and transmission path and effectively control them. Many approaches have been tried in order to identify the noise transmission path of a compressor. However, identification has proven to be difficult since the characteristics of compressor noise are complicated due to the interaction of the compressor parts and gas pulsation. In this study, the statistical energy analysis has been used to trace the energy flow in the compressor and to identify the transmission paths from the noise source to the exterior sound field.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.996-1001
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• 2000

The sound transmission from the machine room where air-conditioner outdoor unit is located into the adjacent room is predicted and evaluated. The software package for statistical energy analysis(SEA) is utilized to determine the transmission losses of multi-layerd panels. To determine the noise level in the machine room, ray tracing method is adopted. The various sound transmission paths have been effectively identified and evaluated by the SEA tool.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1383-1386
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• 2006

This study examines the difference of airborne sound isolation between laboratory and field test. The airborne sound isolation between adjacent dwellings in multi-family buildings is often much less than would be expected from the rated sound reduction index of the nominally-separating wall, due to structure-borne transmission of vibration at the junctions of wall. A variety of construction modifications to control such transmission have also been evaluated. This study presents a factor of the difference for flanking involving joint of wall, and shows the effect of some practical modifications that control the key flanking paths

• 한국멀티미디어학회논문지
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• 제25권9호
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• pp.1348-1355
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• 2022

This study will be an exploratory study from the perspective of IWOM on the intention of word-of-mouth transmission. And based on 256 questionnaire survey data of E-Commerce live broadcast consumers, structural equation modeling is used to explore the paths and mechanisms of influence of consumers' perceived IWOM and perceived value on oral transmission intention in China's E-Commerce live broadcast. The results found that consumers' perceived IWOM had a positive effect on perceived usefulness and perceived entertainment, and that perceived usefulness had a positive effect on purchase intention while perceived entertainment had no direct effect on word-of-mouth transmission intention. Perceived IWOM also indirectly influences willingness to pass on word-of-mouth by affecting perceived value. Among them, the mediating effect of perceived usefulness in the path of perceived network influence on word-of-mouth transmission intention is greater than that of perceived entertainment.

• 한국멀티미디어학회논문지
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• 제21권6호
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• pp.667-677
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• 2018

Since sensor networks consist of sensor nodes with limited energy resources, so efficient energy use of sensor nodes is very important in the design of sensor networks. Sensor nodes consume a lot of energy for data transmission. Clustering technique is used to efficiently use energy in data transmission. Recently, mobile sink techniques have been proposed to reduce the energy load concentrated on the cluster header near a sink node. The CMS(Cluster-based Mobile sink) technique minimizes the generation of control messages by creating a data transmission path while creating clusters, and supports the inter-cluster one-hop transmission. But, there is a case where there is no connectivity between neighbor clusters, it causes a problem of having a long hop data transmission path regardless of local distance. In this paper, we propose a SCBC(Strong connection balancing cluster) to support the path of the minimum number of hops. The proposed scheme minimizes the number of hops in the data transmission path and supports efficient use of energy in the cluster header. This also minimizes a number of hops in data transmission paths even when the sink moves and establishes a new path, and it supports the effect of extending the life cycle of the entire sensor network.

• Journal of Mechanical Science and Technology
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• 제14권10호
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• pp.1051-1060
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• 2000

Linear cyclic systems (LCS's) are a class of systems whose dynamic behavior changes cyclically. Such cyclic behavior is ubiquitous in systems with fundamentally repetitive motions (e. g. all rotating machinery). Yet, the knowledge of the noise and vibration transmission paths in LCS's is quite limited due to the time-varying nature of their dynamics. The first part of this two-part paper derives a generic expression that describes how the noise and/or vibration are transmitted between two (or multiple) locations in the LCS's. An analysis via the Fourier series and Fourier transform (FT) plays a major role in deriving this expression that turns out to be transfer function dependent upon the cycle position of the system. The cyclic nature of the LCS' transfer functions is shown to generate a series of amplitude modulated input signals whose carrier frequencies are harmonic multiples of the LCS' fundamental frequency. Applicability of signal processing techniques used in the linear time-invariant systems (LTIS's to the general LCSs is also discussed. Then, a criterion is proposed to determine how well a LCS can be approximated as a LTIS. In Part II, experimental validation of the analyses carried out in Part I is provided.

• Journal of Communications and Networks
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• 제12권3호
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• pp.275-284
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• 2010

The current multihome-aware protocols (like stream control transmission protocol (SCTP) or parallel TCP for concurrent multipath data transfer (CMT) are not designed for high-capacity and large-latency networks; they often have performance problems transferring large data files over shared long-distance wide area networks. It has been shown that SCTP-CMT is more sensitive to receive buffer (rbuf) constraints, and this rbuf-blocking problem causes considerable throughput loss when multiple paths are used simultaneously. In this research paper, we demonstrate the weakness of SCTP-CMT rbuf constraints, and we then identify that rbuf-blocking problem in SCTP multihoming is mostly due to its loss-based nature for detecting network congestion. We present a simulation-based performance comparison of FAST TCP versus SCTP in high-speed networks for solving a number of throughput issues. This work proposes an end-to-end transport layer protocol (i.e., FAST TCP multihoming as a reliable, delaybased, multihome-aware, and selective ACK-based transport protocol), which can transfer data between a multihomed source and destination hosts through multiple paths simultaneously. Through extensive ns-2 simulations, we show that FAST TCP multihoming achieves the desired goals under a variety of network conditions. The experimental results and survey presented in this research also provide an insight on design decisions for the future high-speed multihomed transport layer protocols.

• 인터넷정보학회논문지
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• 제15권6호
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• pp.1-8
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• 2014

e-러닝의 활성화와 인터넷 비디오 서비스 증가로 인하여 대규모 사용자에 대한 비디오 전송 서비스에 대한 요구가 매년 증가하고 있다. 이러한 요구를 충족시키기 위해 기존 방식은 비디오 서버를 루트 노드로 갖는 트리 구조를 이용하는데 이 방식은 경로상의 한 노드에서만 문제가 발생해도 그 노드 하위 노드들 전체의 서비스가 단절되는 위험성을 안고 있다. 본 연구에서는 다중 경로를 활용한 주문형 비디오 전송 서비스를 제안한다. 기존의 구조에서 사용하는 경로에 백업과 속도 향상을 위한 새로운 경로를 추가함으로서 상위 노드의 문제가 하위 노드의 서비스에 미치는 영향을 방지하여 고품질의 비디오 서비스를 제공할 수 있음을 실험을 통해 보인다.