• Journal of the Optical Society of Korea
• /
• 제12권4호
• /
• pp.249-254
• /
• 2008

In this paper we present an electronic domain solution for chromatic dispersion (CD) monitoring algorithm based on the estimated time domain channel in electronic domain using channel estimation methods. The proposed scheme utilizes kurtosis as a CD measurement, directly computed from the estimated inter-symbol-interference (ISI) channel due to the CD distortion. Hence, the proposed scheme exhibits robust performance under OSNR variation, in contrast to the existing electronic domain approach based on minimum mean squared error (MMSE) fractionally-spaced equalizer taps [1]. The simulation results verify the CD monitoring ability of the proposed scheme.

• 한국컴퓨터정보학회논문지
• /
• 제10권3호
• /
• pp.209-217
• /
• 2005

본 논문에서는 대규모 네트워크에서의 부하분산을 고려한 계층적 도메인간 QoS 라우팅을 제안하였다. 이를 위해 계층적 라우팅에서의 비용 산정 방식을 선계산 방식의 경로계산에서 제안하였고 선계산된 다중경로들 중에서 경로를 선택하는 방안을 제안하였다. 제안한 방식은 도메인으로 분할된 대규모 네트워크의 QoS 라우팅에서 선계산 방식으로 경로를 설정하고, 경로들의 예약 가능성을 높이기 위해 자원 예약 측면에서 가장 좋은 K개의 경로들을 부하분산을 고려하여 계산한다. 또한 이러한 다중 경로들 중에서 비용산정에 근거한 경로선택확률에 따라 경로를 선택하는 방안을 제안하였다. 그리고 제안한 QoS 라우팅 방식을 transit traffic과 intra traffic에 모두 적용하여 도메인간 라우팅과 도메인내 라우팅을 무리 없이 연계하면서 transit traffic을 우선으로 하는 방식을 제안하였다.

• BMB Reports
• /
• 제32권3호
• /
• pp.215-225
• /
• 1999

Phytochromes (with gene family members phyA, B, C, D, and E) are a wavelength-dependent light sensor or switch for gene regulation that underscore a number of photo responsive developmental and morphogenic processes in plants. Recently, phytochrome-like pigment proteins have also been discovered in prokaryotes, possibly functioning as an auto-phosphorylating/phosphate-relaying two-component signaling system (Yeh et al., 1997). Phytochromes are photochromically convertible between the light sensing Pr and regulatory active Pfr forms. Red light converts Pr to Pfr, the latter having a "switch-on" conformation. The Pfr form triggers signal transduction pathways to the downstream responses including the expression of photosynthetic and other growth-regulating genes. The components involved in and the molecular mechanisms of the light signal transduction pathways are largely unknown, although G-proteins, protein kinases, and secondary messengers such as $Ca^{2+}$ ions and cGMP are implicated. The 124-127 kDa phytochromes form homodimeric structures. The N-terminal half contains the tetrapyrrolic phytochromobilin for red/far-red light absorption. The C-terminal half includes both a dimerization motif and regulatory box where the red light signal perceived by the chromophore-domain is recognized and transduced to initiate the signal transduction cascade. A working model for the inter-domain signal communication within the phytochrome molecule is proposed in this Review.

• Journal of Communications and Networks
• /
• 제6권1호
• /
• pp.60-67
• /
• 2004

With the fast growth of Internet and a new widespread interest in optical networks, the unparalleled potential of Multi-Protocol Label Switching (MPLS) is leading to further research and development efforts. One of those areas of research is Path Protection Mechanism. It is widely accepted that layer three protection and recovery mechanisms are too slow for today’s reliability requirements. Failure recovery latencies ranging from several seconds to minutes, for layer three routing protocols, have been widely reported. For this reason, a recovery mechanism at the MPLS layer capable of recovering from failed paths in 10’s of milliseconds has been sought. In light of this, several MPLS based protection mechanisms have been proposed, such as end-to-end path protection and local repair mechanism. Those mechanisms are designed for intra-domain recoveries and little or no attention has been given to the case of non-homogenous independent inter-domains. This paper presents a novel solution for the setup and maintenance of independent protection mechanisms within individual domains and merged at the domain boundaries. This innovative solution offers significant advantages including fast recovery across multiple nonhomogeneous domains and high scalability. Detailed setup and operation procedures are described. Finally, simulation results using OPNET are presented showing recovery times of a few milliseconds.

• Journal of Communications and Networks
• /
• 제8권1호
• /
• pp.106-115
• /
• 2006

The current trend toward the utilization of the Internet as a common means for the offer of heterogeneous services imposes to address the issues related to end-to-end service assurance in the inter-domain scenario. In this paper, we first present an architecture for service management in networks based on service level specifications (SLS). The architecture is designed to be independent both of the specific network technology adopted and of the high level service semantics. Then, we focus on a specific functionality of the proposed architecture: Resource allocation in the multi-domain scenario. A distributed admission control algorithm is introduced, its complexity is evaluated and a comparison with related solutions is provided.

• Bioinformatics and Biosystems
• /
• 제1권2호
• /
• pp.95-98
• /
• 2006

Recent proteomic studies of protein domains require high-throughput and systematic approaches. Since most experiments using protein domains, the modules of protein-protein interactions, require gene cloning, the first experimental step should be retrieving DNA sequences of domain encoding regions from databases. For a large scale proteomic research, however, it is a laborious task to extract a large number of domain sequences manually from several inter-linked databases. We present a new methodology to retrieve DNA sequences of domain encoding regions through automatic database cross-referencing. To extract protein domain encoding regions, it traverses several inter-connected database with validation process. And we applied this method to retrieve all the EGF domain encoding DNA sequences of homo sapiens. This new algorithm was implemented using Python library PAMIE, which enables to cross-reference across distinct databases automatically.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2006년도 춘계학술발표대회
• /
• pp.489-492
• /
• 2006

IDA(Inter-Domain Authentication)는 한 영역의 클라이언트가 다른 영역의 서버에 접근이 가능하게 하는 인증 메카니즘이다. 기존의 커버러스 인증 메카니즘에는 IRA(Inter-Realm Authentication)를 제공하고 있지만 모든 인증방식이 커버러스로 구현된 경우에만 가능하다. 현재 재버의 표준으로는 커버러스 이외에 다른 인증 메카니즘이 병존할 수 있기 때문에 커버러스의 IRA로는 지원이 불가능하다. 따라서 본 연구에서는 재버의 환경에서 다양한 인증 메카니즘이 존재하는 경우에도 적용할 수 있는 IDA를 제안한다. 이 메카니즘을 사용함으로써 중복저장과 동기화에 대한 문제를 해결하여 분산 응용프로그램을 용이하게 설계 구축 할 수 있다.

• 한국정보시스템학회지:정보시스템연구
• /
• 제14권3호
• /
• pp.9-16
• /
• 2005

In this paper, the performance of the WebService architecture for QoS guaranteed connection provisioning in inter-AS domain networks has been measured and analyzed for service publish/inquiry, collection of NMSs ASBR details, source routing by ingress NMS in constraint based routing and connection establishment. From the analysis, it has been found that, the connection between inter-AS domain networks can be established within the usual time limits of 3 seconds by the Web Service architecture. Since no standard solutions have been implemented in Interdomain QoS provisioning, this performance analysis assures Web Service architecture as a promising solution and can be easily implemented in the early stages of MPLS network employment.

• 한국컴퓨터정보학회논문지
• /
• 제11권2호
• /
• pp.223-230
• /
• 2006

휴대 인터넷은 high-speed 무선 인터넷 서비스를 제공하는 새로운 서비스이다. high-speed 무선 인터넷 서비스는 터미널 이동성을 제공한다 휴대인터넷은 2006년에 상업화될 것으로 예상된다. 네트워크 확장과 터미널 이동성은 효율적 소개와 분산 이동 인터넷 서비스를 위해서 보장되어야 한다. 따라서 이 논문에서는 휴대 인터넷의 이동성과 호가장성을 보장하기 위해서 이동 IPv6 기술과 휴대 인터넷의 이동성을 적용한 메커니즘을 제안한다. 제안된 메커니즘은 보안성을 향상시키기 위해서 인터 도메인에서 다이어미터 프로토콜을 적용한다. 또한, 제안된 메커니즘은 데이터 보안성을 제공하기 위해 최소의 시그널 수로 데이터를 안전하게 전송한다.

• ETRI Journal
• /
• 제39권5호
• /
• pp.672-682
• /
• 2017

Video compression exploits statistical, spatial, and temporal redundancy, as well as transform and quantization. In particular, the transform in a frequency domain plays a major role in energy compaction of spatial domain data into frequency domain data. The high efficient video coding standard uses the type-II discrete cosine transform (DCT-II) and type-VII discrete sine transform (DST-VII) to improve the coding efficiency of residual data. However, the DST-VII is applied only to the Intra $4{\times}4$ residual block because it yields relatively small gains in the larger block than in the $4{\times}4$ block. In this study, after rearranging the data of the residual block, we apply the DST-VII to the inter-residual block to achieve coding gain. The rearrangement of the residual block data is similar to the arrangement of the basis vector with a the lowest frequency component of the DST-VII. Experimental results show that the proposed method reduces the luma-chroma (Cb+Cr) BD rates by approximately 0.23% to 0.22%, 0.44% to 0.58%, and 0.46% to 0.65% for the random access, low delay B, and low delay P configurations, respectively.