• Electronics and Telecommunications Trends
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• v.21 no.6 s.102
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• pp.44-52
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• 2006

BcN 백본망은 데이터 트래픽의 생존성 보장과 다양한 서비스를 유연하게 수용하기 위해 다이내믹하게 운용할 수 있어야 한다. 이와 같은 요구사항을 만족하기 위해 광 스위치를 도입하고, 파장 단위의 경로 설정 및 해제를 자동으로 이루어지도록 하는 ASON개념이 적용된 광 회선 분배 시스템이 개발되고 있다. 최근의 광 회선 분배 기술은ROADM을 중심으로 메트로 망에 도입되고 있으며, 특히 제어평면의 도입에 의해 원격프로비저닝 및 자동 망 구성이 가능하게 되었다. 기술적인 측면에서는 PLC 기반의 광스위치를 채택한 1세대 ROADM 시스템에서 WSS 기반의 광 스위치를 채택한 2세대ROADM으로 이동하고 있으며, 이것이 자연스럽게 PXC로 진화할 것으로 보인다. 경제적인 측면에서는 IPTV 등 새로운 서비스를 지원하기 위하여 대규모 시스템 도입이 본격화되고 있으며, 국내의 경우에도 1-2년 내에 상용화 및 시장 진입이 예상되고 있다. 본 고에서는 이러한 광 회선 분배 기술의 전달평면 및 제어평면 기술과 시장 현황 및 향후 전망에 대하여 알아본다.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.728-728
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• 2006

• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.174-179
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• 2005

In the SONET/SDH based ASON, one VC3 connection contains 21 VC12 calls. Hence, it can serve up to 21 VC12 calls. When a new VC12 call arrives, if there exists at least one available VC3 connection in the network, that VC12 call is severed immediately. However, if there is no available VC3 connection, that VC12 call has to wait a certain time, called setup latency, for the a new VC3 connection to be established. This is inconvenient for the customers. On the other hand, if there are more VC3 connections than the network requires, this can waste network resources. In this paper, we proposed the solution for these problems. In order to reduce the number of VC12 calls which have to wait, we setup a new VC3 before all VC12 time slots are occupied. Furthermore, to avoid the waste of the network resources, we do not establish all VC3 connections at the same time, but do establish step by step.

• Information and Communications Magazine
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• v.18 no.11
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• pp.33-43
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• 2001

본 고에서는 광인터넷에 대하여 현재까지 IETE, ITU-T 및 OIF(Optical Internet Forum)을 중심으로 최근에 활발하게 추진되고 있는 표준화 동향을 살펴본다. 특히 광을 기반으로 MPLS(Milti-Protocol Label Switching) 기술을 적용하려는 Generalized MPLS 기술을 중심으로 분석한다. 먼저 IETE에서 MPLS 기술을 중심으로 분석하다 먼저 IETF에서 MPLS WG에서 기본 MPLS 기술에 대한 표준을 지속적으로 작업하고 있으며 여기에서의얻은 기술을 바탕으로 IPO Wg과 CCAMP WG 등에서 광 네트워크 구조를 제안하고 있으며 여기에 새로운 시그널링과 계층적 경로 설정 메커니즘 및 신뢰성 있는 보호/복구 등의 부가적이 기능들을 추가하기 위한 작업을 하고 있다 또한 OIF 에서는 UNI 신호 규격을 정하고 있으며 ITU-T에서 광 전달 네트워크 (OTN)와 관련하여 ASTN/ASON(Automatic Switched Transport Network/Automatic Switched Optical Network)을 포함하여 광 네트워크에 대한 구조적 측면뿐만 아니라 전송 및 망 관리 측면에 대학 규격을 제정 중에 있다.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.2
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• pp.365-371
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• 2021

In the wake of several high-profile corporate accounting scandals, there has been evidence that companies are more eager to hire Chief Executive Officers (CEOs) with an accounting background. This signals that CEOs with an accounting background are recognized and trusted by the corporate world to boost the quality of financial reporting of a company. If it is so, in the context of combating the earnings management, hiring CEOs with an accounting background (being a conservative accounting practitioner), could become one of the effective internal corporate governance mechanisms (CGM) to bring down the earnings management activities. This study attempts to provide insight into the level of conservatism of the CEO with an accounting background. Following Basu (1997) and Khan and Watt (2009), the firm-year measure of conservatism (C_Score) was obtained, which later was associated with the accounting education of the CEO to determine their relationship. As expected, CEOs with accounting background exhibit a higher level of moral reasoning than their non - accounting educated counterparts. The finding of this study is useful to persuade the policymaker to consider lifting the trend of hiring a CEO with an accounting background as one of the best practices that the companies can work out to lessen earnings management activities.

• Journal of Ecology and Environment
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• v.35 no.4
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• pp.279-289
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• 2012

This study conducted a comparative analysis of benthic macroinvertebrate communities in the Fosu and Benya lagoons in Ghana, based on the anthropogenic effect on the two lagoons. Salinity, oxygen, temperature, conductivity, turbidity and pH were measured, invertebrate richness and species densities were determined. The AZTI Marine Biotic Index (AMBI) and multivariate statistics were used to determine the different responses of fauna to pollution. The fauna were categorized into five ecological groups based on the degree of tolerance of the different species to pollution: disturbance-sensitive species; disturbance-indifferent species, disturbance-tolerant species, second-order opportunistic species; and first-order opportunistic species. The Fosu Lagoon supported more pollution tolerant species, whereas the Benya Lagoon had more species that were sensitive to organic enrichment under relatively unpolluted conditions. Chironomus sp., which is adapted to virtually anoxic conditions, was the most abundant in the Fosu Lagoon whereas Nemertea sp. was the most abundant in the Benya Lagoon. The numerical and relative abundance (%) of all 7 taxa in the Fosu Lagoon was 1,359 and 92.35%, respectively. The numerical and relative abundance (%) of all 34 taxa in the Benya Lagoon was 2,459 and 87.52%, respectively. Expectedly, the level of dissolved oxygen in the less saline Fosu Lagoon was higher than that in the more saline Benya Lagoon. The reduced photoperiod and photosynthetic activities of aquatic plants might account for this trend. There is a need to implement comprehensive monitoring and management initiatives for sustaining the ecological health of coastal lagoons in Ghana in order to support the many people that depend upon these ecosystems for their livelihood.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11B
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• pp.707-721
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• 2005

Recently, there has been a dramatic increase in data traffic, driven primarily by the explosive growth of the Internet. Optical networking is believed as a key solution to keep up with the growth, thus, the most pressing issue is how to manage and control large optical networks. Currently, provisioning end-to-end connections across the transport network has involved the network operator, leading to long provisioning times in an era when customers are demanding shorter provisioning time. To address this critical issue, new control intelligence is being studied for use within optical networks to shorten provisioning time. Both the IETF and the ITU-T have been aggressively defining many aspects of a control plane for the next generation convergence transport network. Basically, they are based on the distributed control scheme. In this Paper, we suey the applicability of the centralized control scheme for the provisioning control of optical transport network to utilize its inherent advantages over the distributed control scheme. We discuss new central control architecture, and control procedure. Also, we examine the applicability of the existing IETF routing and signaling protocols to the new control concepts, and then, we propose the additional routing and signaling information elements.

• Journal of KIISE:Information Networking
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• v.29 no.4
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• pp.405-411
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• 2002

Open interfaces in the optica] Internet have been progressed by OIF's ISI, ITU-T ASTN's CCI and IETF's GSMP extensions with optical switching. These open interfaces enable the separation between the control plane and the optical transport plane. This separation allows flexibility in the network, but it suffers more setup delay than the traditional switch-by-switch connection setup. We propose the parallel interworking model, which will reduce the connection setup delay in the open interface of optical Internet. Based on the switch controller's caching capability about networks states, the parallel interworking procedures between signaling protocol and GSMP protocol are performed in the switch controller. We simulated and evaluated our proposed parallel interworking model and the existing sequential interworking model in terms of a connection setup delay and a completion ratio. We observed that the completion ratios of the two interworking models were quite close. However the connection setup delay of parallel interworking model is improved by about 30% compared with that of the sequential interworking model.

• Journal of The Korean Society of Grassland and Forage Science
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• v.12 no.3
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• pp.3-12
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• 1992

Forage grasses and legumes ar$\varepsilon$ the mam component of livestock diets in Canada. There are over 30 million ha of grassland in Canada and there is a large, undeveloped land base in fringe areas suitable for forage production. The short growing s season limits the grassland farming to the southern p parts of Canada. The win!er season is long and in most parts of Canada cold temperatures, fr$\varepsilon$ezmg, and thawing, and diseases exert sever$\varepsilon$ stress on overwintering forage plants. The development of persistent cultivars is essential for sustained production particularly in the fringe areas with short growmg s$\varepsilon$ason. The seasonality of dry matter production is a result of high growth rates in early summ$\varepsilon$r and low dry matter accumulation in late summer and fall. Innovative management practIces a and cultivars with improved regrowth capacity are n necessary to overcome such skewed production pattern and to extend effiectlVe grazmg season l Improved pasture production is an important part of reducing costs in livestock operations and remaining competitive. It is suggested that applying available technology would increase pasture productivity and reduce d$\varepsilon$pendence on stored feeds thus improving profitability of small producers in particeular. Reducing nutrient losses during harv$\varepsilon$stmg, s storage, and feeding is essential for improved production efficiency during confinement. The devclopment of low cost and labor saving methods of ensiling is critical for improved efficiency and profitability of forage based enterprises Livestock industries must respond to consumer preferences for low fat and cholesterol foods. Research and development of entire production systems is emphasized for dev$\varepsilon$loping viabl$\varepsilon$ enterprises. It is increasingly difficult to secure resources for r$\varepsilon$search, education, and extension, and alliane$\varepsilon$s and cooperation must expand among organizations with interests in forage based livestock systems.