• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.8 no.6
• /
• pp.77-88
• /
• 2008

This paper addresses the implementation of FTTH system based on G-PON technology. This system supports the duplication function that can switchover both TDM and data routes within 10msec. This system consists of OLT and ONU/ONT. G-PON OLT supports the maximum 32 2.5Gbps interfaces, and then has the flexibility and the scalability for supplying digital communication and broadcasting convergence service in the near future. OLT system consists switch module, subscriber module, processor module, and G-PON link module, and has the operating system based on Linux. ONU is installed in customer premise to supply TPS (Triple Play Service). Also ONT has the dedicated interface for IP-TV to improve the transmission characteristics of IP-TV signal.

• Journal of Information Technology Services
• /
• v.12 no.1
• /
• pp.323-340
• /
• 2013

As the importance of collaboration becomes critical in today's open and complex business environment network, the issues and solutions on compatibility and reusability between different kinds of applications are being increasingly important as well in systems analysis and design. And therefore, service-centered SOA is receiving attention in such business environment as a strategic approach that makes possible for prompt action according to the needs of users and business process. Various implementation methodologies have been proposed for SOA, however, in practical aspects most of them have some problems since they fail to propose specific policies in definition and identification of services for the exact user requirements and business situations. To solve or alleviate those problems, this paper suggests a new service identification model based on hierarchical ontology, where three different ontologies such as business ontology, context ontology and service ontology are proposed to define the relationship and design the link between user requirements, business process, applications and services. Through a suggested methodology in this paper, it would be possible to provide proactive services that meets a variety of business environments and demands of user. Also, since the information can be modified adaptively and dynamically by hierarchical ontology, this study is expected to play a positive role in increasing the flexibility of systems and business environments.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.24
• /
• pp.51-72
• /
• 2004

Over the past fifty years, the share of the World's shipping fleet operating under open registry has grown from 4 % to almost half of the total tonnage. While there has been strong opposition based on the costs of maritime disasters and opposition both from the traditional maritime nations, which have suffered erosion of their fleets, and from labour unions, which point to worker exploitation, the shipping companies have found the greater operational and financial flexibility which accompanies open registry to be a considerable attraction The paper consists of seven sections. Section 1 explains the background and of the study. Section 2 reviews the characteristics and definition of FOC. Section 3 is to identify ship register categories and their competitive conditions. Section 4 tackles the emerging forces of globalisation-the advent of FOC. Section 5 deals with legal maritime framework. Section 6 tackles the current structure and characteristics of FOC vessels. Some concluding comments follow in the last section.

• Journal of Communications and Networks
• /
• v.2 no.1
• /
• pp.35-45
• /
• 2000

this paper presents the concept of "mobile ATM', a proposal for third-generation (3G) mobile communication network infrastructure capable of supporting flexible evolution of radio technologies from today's cellular and data services towards future wireless multimedia services. Mobile ATM provides generic mobility management and QoS-based transport capabilities suitable for integration of multiple radio access technologies including cellular voice. wireless data, and future broadband wireless services. The architecture of a mobile ATM network is outlined in terms of the newly-defined "W-UNI" interface at the radio link and "M-UNI"and "M-UNI" interface which supports unified access for WATM and non-ATM mobile terminals through corresponding interworking functions (IWF) is explained. leading to an understanding of how different radio access technologies are supported by the same ATM-based core network infrastructure. Generic mechanisms for handoff and location management within the core mobile network are discussed. and related protocol extensions over the "W-UNI" and "M-UNI/NNI"interfaces are proposed. the issue of "crossover switch (COS)" selection in mobile ATM is considered, and a unified handoff signaling syntax which supports flexibility in COS selection is described. Typical signaling sequences for call connection and handoff using the proposed protocols are outlined. Experimental results form a proof-of-concept mobile ATM network prototype are presented in conclusion.

• Environmental and Resource Economics Review
• /
• v.21 no.2
• /
• pp.301-319
• /
• 2012

The primary purpose of Renewable Portfolio Standard (RPS) is to facilitate investment in renewable energy technology. Since emission trading program has similar purpose, it is conceivable to attempt to link RPS and emission trading program through interlinked markets. RPS in Korea with single REC and emission allowance markets has particular advantages for constructing linkages between two markets. This paper provides a real option model to examine investment effects of linkage of RPS to the trading program. Emission permit price and REC price are assumed to follow stochastic processes and renewable investment is irreversible. The result shows that linked market provides further incentive for renewable investment by raising managerial flexibility for power companies.

• The Journal of Asian Finance, Economics and Business
• /
• v.7 no.5
• /
• pp.237-248
• /
• 2020

The purpose of this study is to investigate and reconfirm the research instruments and variables that have been developed by prior study and built new concepts from empirical research results. Besides analyzing the essential role of fundamental, rational, and psychology aspects to increase employee's intention to stay in a company, which is useful for the development of human resource development strategies for millennial workers in the future. A total of 438 non-student male respondents aged 23-36 years, with unmarried status and not working in the SOE sector or as a civil servant, were surveyed with questionnaires. The study was conducted in Makassar, Indonesia. Data collection uses a survey with the second-order model approach and regression with control variables. The findings of this study suggest the existence of an inter-relationship between fundamental, rational and psychological aspects. They are inseparable and have a positive and significant influence. Broadly speaking, the link between fundamental, psychology and rational aspects states that the decision for millennial male workers to stay in the company will depend on whether the company has a good image and reputation, the level of attention the organization pays to career development, is competent, and applies regulations and rules with flexibility.

• Broadcasting and Media Magazine
• /
• v.11 no.1
• /
• pp.68-77
• /
• 2006

The Cognitive Radio (CR) technology is a promising solution for exploiting the limited spectrum resources and providing flexibility of spectrum usage. Future interactive broadcasting service can be realized by utilizing CR concept, since the up-link return channel can be found by the spectrum sensing method, which is core functional block of the CR system. In this paper, the spectrum sensing technologies of CR system is presented. First the system architecture of the CR with spectrum sensing block is presented. The suggested spectrum sensing technique consists of the coarse and the fine spectrum sensing. The coarse spectrum sensing technique adopted the wavelet transform to provide the multi-resolution sensing feature - Multi-Resolution Spectrum Sensing (MRSS). The fine spectrum sensing technique uses the beneficial properties of the autocorrelation function Analog Auto-Correlation (AAC). The simulation results for the proposed sensing technologies are presented for various incumbent signals.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.6 no.9
• /
• pp.2231-2252
• /
• 2012

With the prevalence of diverse services-oriented applications, such as IPTV systems and on-line games, the current underlying communication networks face more and more challenges on the aspects of flexibility and adaptability. Therefore, an effective and efficient multicast routing mechanism, which can fulfill different requirements of different personalized services, is critical and significant. In this paper, we first define the neighbor gradient, which is calculated based on the weighted sum of attributes such as residual link capacity, normalized hop count, etc. Then two distributed multicast routing algorithms which are neighbor Gradient-based Multicast Routing for Static multicast membership (GMR-S) and neighbor Gradient-based Multicast Routing for Dynamic multicast membership (GMR-D), are proposed. GMR-S is suitable for static membership situation, while GMR-D can be used for the dynamic membership network environment. Experimental results demonstrate the effectiveness and efficiency of our proposed methods.

• Proceedings of the KIEE Conference
• /
• 2001.04a
• /
• pp.349-352
• /
• 2001

FACTS technology is developed into the sophisticated system technology which combines conventional power system technology with power electronics, micro-process control, and information technology. Its objectives are achieving enhancement of the power system flexibility and maximum utilization of the power transfer capability through improvements of the system reliability, controllability, and efficiency [1]. As a series and shunt compensator, UPFC consists of two inverters with common dc link capacitor bank. It controls the magnitude of shunt bus voltage and real and reactive power flow of transmission line[2]. In this paper, we present the design, implementation and test results of developed 20kVA level prototype UPFC. It is applied to power system simulator and controls the real and reactive power flow and shunt bus voltage magnitude.

• Proceedings of the KIEE Conference
• /
• 2001.07a
• /
• pp.374-376
• /
• 2001

FACTS technology is developed into the sophisticated system technology which combines conventional power system technology with power electronics, micro-process control, and information technology. Its objectives are achieving enhancement of the power system flexibility and maximum utilization of the power transfer capability through improvements of the system reliability, controllability, and efficiency[1]. As a series and shunt compensator, UPFC consists of two inverters with common dc link capacitor bank. It controls the magnitude of shunt bus voltage and real and reactive power flow of transmission line[2]. In this paper, we present the design and control algorithm of UPFC simulator for KERI simulator. As a control algorithm is implemented by digital controller, we consider sample-and-hold of signals In this simulation, we use EMTDC/PSCAD V3.0 software which can simulate instantaneous voltage and current.