• 소음진동
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• 제2권1호
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• pp.21-31
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• 1992

In the previous paper, we report a practical floor impact sound level prediction method for a heavyweight impact source(Tire), soft impact source such as children jumping and running. According to these results, the calculated value and the measured value correspond comparatively well, regardless of differences in the floor structures. And the floor impact sound for a heavyweight impact source, soft source was strongly influenced by structural factors such as floor slab stiffness and peripheral support conditions. But the floor impact sound for a light impact source (Tapping machine), hard impact source was influenced by resilient layers, composed of multi-layer in floor structures. Thus, In this paper, 4 actual floor structures, all with differing resilient layers, were calculated using impedance method. When these calculation values were compared with the measured values, approximately all the values fell with one rank of the sound insulation grade, reference curve(L curve) by the JIS standard. So, a sample of measured values and calculated values from floor structures is presented to show the accuracy and appropriateness of the impedance method in domestic.

• 한국통신학회논문지
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• 제35권9B호
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• pp.1266-1271
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• 2010

본 논문에서는 PMIPv6 망에서 NEMO 지원 시 다양한 시나리오에 따라 발생하는 문제점을 기술하고, 이를 해결하기 위한 binding 방안을 제안하였다. 제안한 방안은 새롭게 정의한 네트워크-계층 메시지를 이용하여 네트워크 기반의 이동성 절차를 수행함으로써 중복되어 터널이 생성되는 문제점을 해결하였으며 핸드오버 지연시간을 줄이고 호스트가 이동성과 관련된 절차에 참여하지 않아도 되는 binding 메커니즘이다. 그리고 성능 분석을 통해 제안한 방식이 IETF NELMM WG의 방안과 비교하여 패킷 손실, 핸드오버 지연시간과 평균 패킷 처리량의 관점에서 성능이 향상되었음을 확인하였다.

• 한국초전도ㆍ저온공학회논문지
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• 제14권1호
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• pp.30-33
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• 2012

A double pancake winding method is widely used to make the superconducting magnet, using high temperature superconductor (HTS) tape. In the double pancake winding method, the joints with contact resistances between double pancake coils are inevitably needed. The electrical joule heating on the contacts causes refrigerant loss during operation. And a space outside the winding, for splices and mechanical support, is more than that for its layer-wound equivalent. In this paper, a double pancake winding method in order to reduce the number of the joints was proposed. Both of the double pancake coils using the conventional winding method and the proposed winding method have been fabricated and tested to make the solution technically feasible in the double pancake winding method. Especially, critical-current tests of the fabricated double pancake coils were conducted in order to show the same performance and confirm contact resistances between double pancake coils.

• 한국막학회:학술대회논문집
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• 한국막학회 2005년도 추계 총회 및 학술발표회
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• pp.133-147
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• 2005

In order to investigate applicability for 2,2,2-trifluoroethyl methacrylate (TFEMA) produced by esterification of 2,2,2-trifluoroethanol(TFEA) and methacrylic acid(MA) using pervaporation membrane, poly(vinyl alcohol) (PVA) composite membranes were prepared with glutaraldehyde(GA) onto porous polyethersulfone(PES) support. The degree of crosslinking and thickness of PVA coating layer were analyzed by swelling test and SEM(scanning electron microscopy), respectively. Pervaporation test was done with two feed mixures; TFEA/water, MA/water. The pervaporation data were obtained as a function of content of crosslinking agent, feed composition, and operating temperature, respectively. In case of TFEA-water(90/10 wt%) feed mixture at $80^{\circ}C$, the optimized membrane showed the high permeation flux of 1.5 $kg/m^2hr$ and separation factor of 320. In case of MA-water(90/10 wt%) feed mixture, the membranealso showed high permeation flux of 2.3 $kg/m^2hr$ and separation factor of 740 in same conditions.

• 한국통신학회논문지
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• 제25권3B호
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• pp.487-492
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• 2000

ABR (Available Bit Rate) 서비스는 ATM (Asynchronous Transfer Mode) 에서 데이터 응용을 지원하기 위하여 개발되었으며, TCP(Transmission Control Protocol) 는 현재 사용되는 데이터망에서 가장 널리 이용되는 트랜 스포트 계층 프로토콜이다. 따라서 TCP over ABR의 성능 향상은 대단히 중요한 문제이다. 본 논문에서는 RM (Resource Management)셀의 정보를 이용한 TCP congestion 윈도우 크기 조절을 제안한다. 제안된 방식의 사용으로 TCP 윈도우 크기 결정에 보다 신뢰성 있는 망 정보 (RM 셀 내의 ER 값)를 사용하게 된다. 시뮬레이션은 다양한 망 상황과 다양한 망 구성에서 행하여졌으며 시뮬레이션 결과는 제안된 방식의 시용으로 TCP의 성능이 월등히 향상됨을 보인다.

• 정보와 통신
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• 제13권3호
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• pp.61-70
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• 1996

본 논문에서는 ATM Forum에서 제안하고 있는 LAN 에뮬레이션 서비스 구조를 소개하였다. LAN 에뮬레이션은 기존의 방대한 LAN 응용 소프트웨어들을 ATM 망에서 그대로 사용하기 위하여 ATM 망에서 기존의 비연결형 LAN 서비스를 에뮬레이트하는 MAC 계층 서비스를 제공한다. LAN 에뮬레이션에 의하여 ATM 망상에는 논리적인 오버레이 망인 에뮬레이트된 망이 형성되는데, LAN 에뮬레이션 서비스는 에뮬레이트된 LAN의 각 종단 시스템에 설치되는 LAN 에뮬레이션 클라이언트(LEC)들의 집합과 세 가지의 논리적 서비스 요소들로 구성된다. 이 세 가지의 논리적 서비스 요소들은 LAN 에뮬레이션 구성 서버(LE 서버), Broadcast and Unknown 서버(BUS)라고 불리우며, LF, 클라이언트는 이 세 가지 서버가 제공하는 서비스를 이용하여 기존 LAN과 ATM망과의 상호 연동 및 ATM 망에서의 LAN 응용간 투명한 통신을 지원한다.

• Membrane and Water Treatment
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• 제5권3호
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• pp.171-182
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• 2014

Organic compounds are adsorbed on RO/NF membranes, and the adsorption may influence the rejection of organic compounds by the membranes. Because almost RO/NF membranes are composite membranes, the results obtained by adsorption experiment with using membrane pieces are unable to avoid the influence by the support membrane. In this work, the interaction between membrane polymer and organic solutes was examined by an inverse HPLC methodology. Poly (m-phenylenetrimesoylate), the constituent of skin layer of RO/NF membranes, was coated on silica gel particles and used as a stationary phase for HPLC. When water was used as a mobile phase, almost hydrophilic aliphatic compounds were not effectively adsorbed on the stationary phase, although hydrophobic compounds were slightly adsorbed. The results indicated that the hydrophilic aliphatic compounds are useful probe solutes to examine the molecular sieving effect of a membrane. When water was used as a mobile phase, the aromatic compounds were strongly retained, and therefore $CH_3CN/H_2O$ (30/70) was used as a mobile phase. It was revealed that the adsorption of aromatic compounds was controlled by stacking between solute and polymer and was hindered by non-planar structure and substituents.

• Journal of Information Processing Systems
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• 제14권4호
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• pp.892-903
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• 2018

The paper proposes a novel gait recognition algorithm based on feature fusion of gait energy image (GEI) dynamic region and Gabor, which consists of four steps. First, the gait contour images are extracted through the object detection, binarization and morphological process. Secondly, features of GEI at different angles and Gabor features with multiple orientations are extracted from the dynamic part of GEI, respectively. Then averaging method is adopted to fuse features of GEI dynamic region with features of Gabor wavelets on feature layer and the feature space dimension is reduced by an improved Kernel Principal Component Analysis (KPCA). Finally, the vectors of feature fusion are input into the support vector machine (SVM) based on multi classification to realize the classification and recognition of gait. The primary contributions of the paper are: a novel gait recognition algorithm based on based on feature fusion of GEI and Gabor is proposed; an improved KPCA method is used to reduce the feature matrix dimension; a SVM is employed to identify the gait sequences. The experimental results suggest that the proposed algorithm yields over 90% of correct classification rate, which testify that the method can identify better different human gait and get better recognized effect than other existing algorithms.

• 한국위성정보통신학회논문지
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• 제6권2호
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• pp.84-90
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• 2011

IP 기반의 이동 네트워크에서 페이징 메커니즘을 IP 계층에서 처리하는 기술(즉, IP 페이징)은 이동 단말의 전력 소모와 위치 등록 시그널링 부하를 감소시켜주며, 이기종 무선 액세스 기술들을 지원하는 것을 가능하게 한다. 그러나, 통신이 매우 빈번한 환경 하에서는 증가하는 페이징 시그널링 부하와 잦은 페이징 지연으로 인하여 오히려 IP 페이징의 사용은 역효과를 초래할 수도 있다. 따라서, 본 논문에서는, 이러한 IP 페이징의 문제점을 해결하고자, 이동 단말이 자신의 프로파일 정보에 기반하여 선택적인 위치 등록 및 페이징을 수행할 수 있도록 하는 비용 효율적인 IP 페이징 기법을 제안한다. 성능 평가 결과, 제안 기법은 IP 기반의 계층적 이동 네트워크에서 상당한 정도의 페이징 시그널링 부하와 잦은 페이징 지연을 감소시킬 수 있다는 것을 보여준다.

• Journal of Information Processing Systems
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• 제11권3호
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• pp.465-482
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• 2015

IEEE 802.11p is a standard MAC protocol for wireless access in vehicular environments (WAVEs). If a packet collision happens when a safety message is sent out, IEEE 802.11p chooses a random back-off counter value in a fixed-size contention window. However, depending on the random choice of back-off counter value, it is still possible that less important messages are sent out first while more important messages are delayed longer until sent out. In this paper, we present a new scheme for safety message scheduling, called the enhanced message priority mechanism (EMPM). It consists of the following two components: the benefit-value algorithm, which calculates the priority of the messages depending on the speed, deceleration, and message lifetime; and the back-off counter selection algorithm, which chooses the non-uniform back-off counter value in order to reduce the collision probability and to enhance the throughput of the highly beneficial messages. Numerical results show that the EMPM can significantly improve the throughput and delay of messages with high benefits when compared with existing MAC protocols. Consequently, the EMPM can provide better QoS support for the more important and urgent messages.