• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.9
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• pp.497-507
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• 2014

This paper investigates the standard features of Carrier aggregation (CA), the related UE RF requirements in 3GPP release 12 and estimated CA evolution in future. The main CA feature of 3GPP release 12 in WG4 perspectives includes 2Uplink(UL) CA, 3Downlink(DL) CA and TDD-FDD CA. To support these features in UE, UE-to-UE coexistence problem and RF requirements generated by unwanted emissions such as inter-modulation and harmonics are analyzed. Also, future CA technology such as LTE in unlicensed bands is described.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.11
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• pp.1052-1057
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• 2004

Bluetooth technology is essentially a method for wireless connectivity of a diverse set of devices ranging from PDAs, mobile phone, notebook computers, to another equipments, The bluetooth system both point-to point connection and point-to multipoint connection. In point-to multipoint connection, the channel is shared among several bluetooth devices. Two or more devices sharing the same channel form a piconet. There one master device and up to seven active slave devices in a piconet. The radio operates in the unlicensed 2.45GHz ISM band. This allows users who travel world-wide to use bluetooth equipments anywhere. Since the link is based on frequency-hop spread spectrum, multiple channels can exist at the same time. The bluetooth standard ha s been suggested that bluetooth equipments can be used in the short-range, maximum 100 meters. It has been defined that the time takes to setup and establish a bluetooth connection among devices is 10 seconds. It is a long time and may be a cause to lose a chance of finding other non-fixed devices. We propose a routing protocols for scatternets which can be used to control a mobile units(MUs) in this network. The proposed routing protocol is composed of two kinds of bluetooth information, access point(AP) and MU.

• Journal of information and communication convergence engineering
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• v.8 no.3
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• pp.273-276
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• 2010

Opportunistic spectrum access (OSA) allows unlicensed users to share licensed spectrum in space and time with no or little interference to primary users, with bring new research challenges in MAC design. We propose a cognitive MAC protocol using statistical channel information and selecting appropriate idle channel for transmission. The protocol based on the CSMA/CA, exploits statistics of spectrum usage for decision making on channel access. Idle channel availability, spectrum hole sufficiency and available channel condition will be included in algorithm statistical information. The model include the control channel and data channel, the transmitter negotiates with receiver on transmission parameters through control channel, statistical decision results (successful rate of transmission) from exchanged transmission parameters of control channel should pass the threshold and decide the data transmission with spectrum hole on data channel. The proposed protocol's simulation will show that proposed protocol does improve the throughput performance via traditional opportunistic spectrum access MAC protocol.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.2 s.93
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• pp.194-198
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• 2005

A novel ultra wideband microstrip-fed circular patch antenna having band stop characteristic in UNII band is presented. The band stop characteristic is realized by inverted-U shaped slot. The range of stop bandwidth can be adjusted by changing the length of the slot. The measured impedance bandwidth of the proposed antenna is from 2.9 GHz to 12.1 GHz with the stop band from 4.9 GHz to 6 GHz for VSWR<2. This antenna shows a monopole-like radiation pattern and flat gain characteristic throughout the operating frequency band.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.59
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• pp.159-178
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• 2013

International factoring is very useful to transfer credit risk, to promote cash flow, to collect debt and to reduce cost and expenses. However, International factoring system in china shows imperfection especially in gap of legal vacuum and its limit to be developed. Here I suggest a practical alternative for development of International factoring system in china as follow. First, legal environment in China for factoring system should be rearranged. Even law and contract law have relative clauses for factoring system there are many difficulty to be applied. It is necessary to prepare legal ground for factoring system. Second, without recourse for International factoring system should be fixed. Without recourse is the essential point for factoring system in international trade. In fact chinese factors are partially applied only for those big global companies. However International factoring system is especially useful for small-medium companies lacked of a good credit rating. It is necessary to promote special factors by combining financial organizations as it does in developed countries. Third, they need to make legal ground to prohibit unlicensed factoring companies. Forth, they need to educate usefulness of factoring system. The settlement system in China is to be developed by systematic researches and promotion for International factoring system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.7
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• pp.2231-2245
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• 2014

Cognitive Radio (CR) has very promising potential to improve spectrum utilization by allowing unlicensed Secondary Users (SUs) to access the spectrum dynamically without disturbing licensed Primary Users (PUs). Mitigating interference is a fundamental problem in CR scenarios. This is particularly problematic for deploying CR in cellular networks, when users are located at the cell edge, as the inter-cell interference mitigation and frequency reuse are critical requirements for both PUs and SUs. Further cellular networks require higher cell edge performance, then SUs will meet more challenges than PUs. To solve the performance decrease for SUs at the cell edge, a novel Dynamic Spectrum Allocation (DSA) scheme based on Game Theory is proposed in this paper. Full frequency reuse can be realized as well as inter-cell interference mitigated according to SUs' sensing, measurement and interaction in this scheme. A joint power/channel allocation algorithm is proposed to improve both cell-edge user experience and network performance through distributed pricing calculation and exchange based on game theory. Analytical proof is presented and simulation results show that the proposed scheme achieves high efficiency of spectrum usage and improvement of cell edge SUs' performance.

• IE interfaces
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• v.21 no.3
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• pp.283-293
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• 2008

It is important to choose and develop right business model in the process of implementing the ubiquitous service concept. In particular, it is also required to build a method which can assist in establishing a business model in a competitive perspective to differentiate business strategy. However, we could not find the existing studies which tried to develop business model including methods on how to differentiate business strategy in a competitive environment. In this study, we propose an ontology for repository of ubiquitous business model and address on how to apply the proposed business model repository to real ubiquitous industry. We also built a repository of unlicensed wireless device industry to check the applicability of proposed ubiquitous business model ontology and to show the various examples. We expect that building the business model repository contributes to reduce the redundancy and inefficiency for industry as well as to increase likelihood of business success for an individual company.

• The Journal of Internal Korean Medicine
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• v.38 no.5
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• pp.555-563
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• 2017

Objectives: This case report describes a patient who had suffered a stroke and who was treated for a long period with herbal medicine in combination with a Western medicine. Methods: Changes in liver function and renal function laboratory tests were measured while the patient took herbal medicine during the 1190 days of hospitalization. Results: During the hospitalization period, the liver function test (LFT) levels were elevated two fold, but after taking the herbal medicine, the LFT levels were stabilized and have remained stable since. Conclusions: The high risk of prescribing herbal medicine by an unlicensed person and the possibility of long-term herbal medicine usage for stabilizing liver function test were shown.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.4
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• pp.1192-1207
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• 2014

Dynamic spectrum sharing is a key technology to improve spectrum utilization in wireless networks. The elastic spectrum management provides a new opportunity for licensed primary users and unlicensed secondary users to efficiently utilize the scarce wireless resource. In this paper, we present a game-theoretic framework for dynamic spectrum allocation where the primary users rent the unutilized spectrum to the secondary users for a monetary profit. In reality, due to the ON-OFF behavior of the primary user, the quantity of spectrum that can be opportunistically shared by the secondary users is limited. We model this situation with the renewal theory and formulate the spectrum pricing scheme with the Bertrand game, taking into account the scarcity of the spectrum. By the Nash-equilibrium pricing scheme, each player in the game continually converges to a strategy that maximizes its own profit. We also investigate the impact of several properties, including channel quality and spectrum substitutability. Based on the equilibrium analysis, we finally propose a decentralized algorithm that leads the primary users to the Nash-equilibrium, called DST. The stability of the proposed algorithm in terms of convergence to the Nash equilibrium is also studied.

• The Journal of Korean Medical History
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• v.28 no.1
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• pp.121-133
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• 2015

Objectives : The purpose of this study is to suggest how to interpret the 'practice of Korean Medicine', differentiating it from 'medical practice'. Methods : I analyze the legislations and precedents regarding the practice of Korean Medicine. Results : The Korean Medicine and Pharmaceutics Promotion Act defines 'practice of Korean Medicine' and it clearly differentiates it from the definition of 'medical practice'. However, the scope of this definition is somewhat restricting and it can violate doctors of Korean Medicine's right to equality and their academic freedom. Thus, the application of this definition of the 'practice of Korean Medicine' should be limited to the field of research and development. Meanwhile, criteria of distinguishing 'practice of Korean Medicine' from 'medical practice', which used to make a sharp distinction between Medicine and Korean Medicine by rigorously applying their academic standards, are now focusing more on protecting and improving health of the people. Discussions & Conclusions : I suppose that the distinction between the 'practice of Korean Medicine' and 'medical practice' will be more focused on public health rather than the academic stance of those two medical fields. Meanwhile, in accordance with dualistic medical system, the mutual usage of medical equipment in the area of 'treatment' should be limited while it should be allowed in the area of 'diagnosis' if it satisfies requirements suggested by the Constitutional Court.