• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1191-1199
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• 2009

As the Internet service evolves from the best effort data service to a multimedia service such as a mix of voice, data and video, a need for the guarantee of the quality of service to network services became one of the hot issues for the network operators. On the other hand, the introduction of the multimedia services over the IP network requires a managed differentiated service that adopts a prioritized treatment of packets. This incurs a need for a differentiated pricing scheme for the packets that receive different level of quality of service. This work proposes an analytic framework about packet pricing scheme for these services, and investigate the effect of service differentiation to the packet price for each class. Via numerical experiment, we validate our argument and illustrate the implication of the work.

• Journal of Technology Innovation
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• v.10 no.2
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• pp.107-129
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• 2002

Expansion and enhancement of information and communication infrastructure can create a market closer to an ideal type for a perfect competition, utilizing a cyber space in the network (with the expanded usage of Internet and e-commerce) and it could be a market of a monopolistic form. The government can take one of the two approaches responding to this monopolization of the digital market. First, the government maintains laissez-faire policy since the monopoly cannot be maintained over a long period of time due to an increasing in the production, decrease in the price, profit resulting from this and rapid technology evolution. Second, the government can actively interrupt the monopolization of the digital market. Monopolization in a digital market can lead to a market failure. Unstable market structure and too much frequent merger and acquisition contribute to making the digital market very dynamic. Information goods exchanged in the digital market have the features of very low marginal cost required to copy the original product whereas its initial fixed cost is very high. This explains why the information products are not priced based on the existing marginal price determination principles and why companies producing them have various product sales strategies (price/product differentiation strategy, and other sales strategies).

• Korean Journal of Oriental Medicine
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• v.11 no.1
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• pp.109-118
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• 2005

In a field of oriental medicine, it is necessary to collect systemically clinical data and integrate. Input data items was decided, then categorized by the modules through discussion of the institute and hospitals. Items are information of patient, history, aspects of occurrence, pattern identification, prescriptions of herbal medicine, the results of biochemical serum examination, blood cell count, urine analysis, CT, MRI, Chest PA, EKG etc. Factors in oriental medicine are Sasang constitution, Stroke-Pattern-Identification(china), differentiation of cold and heat syndrome. This tool was constructed by using Microsoft-Access 2000 and Microsoft Visual Basic 6.0. Furthermore this web-based system could be applied to multi-center clinical investigation.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.1027-1030
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• 2014

대중음악과 스마트폰 기술이 발달하면서 사용자가 직접 음악을 검색할 수 있는 내용 기반 음악 검색 기술이 연구되었다. 그 결과 허밍을 사용하여 음악을 검색할 수 있는 음악 검색 시스템이 개발되었지만, 검색 속도가 느리고 검색 결과가 부정확한 시스템이 많다. 본 논문에서는 음원의 주파수 변화율을 측정하고 이를 코사인 유사도 알고리즘을 이용하여 유사도를 측정하는 음악 검색 시스템을 설계하였고, 각 설계요소를 설명한다. 새로 설계한 음악 검색 시스템을 기반으로 한 실험을 통하여 기존의 음악 검색 시스템과 유사한 성능이 나오는 것을 확인하였으며 본 논문에서 제시한 새로운 음악 검색 시스템은 기존 음악 검색 시스템보다 구조가 단순하면서도 유사한 결과를 내고 있다.

• Reproductive and Developmental Biology
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• v.29 no.2
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• pp.69-73
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• 2005

The hematopoietic growth factor erythropoietin (EPO) is required for the maintenance, proliferation, and differentiation of the stem cells that produce erythrocytes. To analyse the biological activity of the recombinant human EPO (rec-hEPO), we have cloned the EPO cDNA and genomic DNA and produced rec-hEPO in the CHO cell lines. The growth and differentiation of EPO-dependent human leukemic cell line (F36E) were used to measure cytokine dependency and in vitro bioactivity of rec-hEPO. MIT assay values were increased by survival of F36E cells at 24h or 72h. The hematocrit and RBC values were increased by subcutaneous injection of 20 IU (in mice) and 100IU(in rats) rec-hEPO. Hematocrit values remarkably increased at $13.2\%$ (in mice) and $12.2\%$ (in rats). The pharmacokinetic behavior with injection of 6 IU of rec-hEPO remained detectable after 24 h in all mice tested. The highest peat appeared at 2h after injection. The long half-life of rec-hEPO is likely to confer clinical advantages by allowing less frequent dosing in patients treated for anemia. These data demonstratethat ree-hEPO produced in this study has a potent activity in vivo and in vitro. The results also suggest that biological activity of ree-hEPO could be remarkably enhanced by genetic engineering that affects the potential activity, including mutants with added oligosaccharide chain and designed to produce EPO-EPO fusion protein.

• Korean Institute of Interior Design Journal
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• v.22 no.4
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• pp.167-177
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• 2013

The environmental considerations should be taken into full consideration in order to make the use of ground space as comfort and efficient as that of ground space. The visual environmental factors which provide visual informations in underground spaces where the environmental information can be acquired only by the surroundings expand their role as affordance for wayfinding. This study focuses on the visual performance evaluation of wayfinding factors on the subway transfer station platform and aisle as major space for movement in four subway transfe stations and analyzes the material, pattern, color, and lighting provided by the visual environment in underground space as directional marked label, regional differentiation and sign system. The results of this study comes are as follows. First, As to the directional marked label at the subway platform and transfer aisle, following patterns are colors, finishing materials and lighting for the sake of safety and convenience, And regional differentiation, following colors are patterns for the space division. Finally sign system which practically provides the most information, however, it is most insufficient to be a space-preception element. Second, According to the type of platform structures, such as an island platform and a separate platform, the main areas of and necessity for the space-perception elements may bring about changes. Third, these four stations that has been analyzed for this study, lighting, compared with color, finishing material and pattern, has been highly insufficient to be a perception element.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11B
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• pp.698-706
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• 2005

In this paper, we investigate the parameters of the IEEE 802.11e MAC protocol, CWmin and AIFS, in terms of their capability of QoS control. The delay and the bandwidth performances are selected as the QoS medics to examine the characteristics of those parameters. A policy on MAC parameters usage, thereby, is proposed. We regard the MAC-level traffic classification as the differentiation in the channel accessibility, and thus the delay differentiation is referred to a main issue of the class-level QoS control. Realizing the tight relationship between the delay performance and the parameter AIFS, we derive an analytical expression of their relationship through an analysis of the MAC mechanism. Various simulations are examined which show the validity of our assertions, and a policy on the parameters usage is proposed based on those observations.

• Journal of KIISE:Information Networking
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• v.32 no.6
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• pp.676-686
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• 2005

The Internet users as well as network providers are eager to have different qualities of service among users beyond the best-effort. In this paper, we propose a scheduling algorithm that provides a differentiated service in the granularity of user sessions. The proposed algorithm is a Hierarchical Deficit Round-Robin (H-DRR) algorithm that is an extension of an existing DRR algorithm. A main advantage is that H-DRR provides service differentiation for throughput-intensive applications such as FTP as well as delay-sensitive applications such as telnet or VoIP without distinguishing the types of applications. The most importance in providing a service differentiation in term of network providers is to have controllability and predictability. We show that H-DRR is superior to DRR in terms of controllability and predictability through both mathematical analysis and simulation experiments. Nevertheless, H-DRR requires O(1) complexity for implementation.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.6
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• pp.676-688
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• 2014

The IEEE 802.11e EDCA (Enhanced Distributed Channel Access) mechanism has been proposed to improve the QoS (Quality of Service) of various services in WLANs (Wireless Local Area Networks). By differentiating the channel access delay depending on ACs (Access Categories), this mechanism can provide the relative service differentiation among ACs. In this paper, we consider that WLAN is deployed in medical environments to transfer medical traffic and we reveal that the quality of the medical traffic (in particular, ECG signals) is significantly deteriorated even with the service differentiation by IEEE 802.11e EDCA. Also, we analyze the reason for performance degradation and show that IEEE 802.11e EDCA has difficulty in protecting the transmission opportunity of high-priority traffic against low-priority traffic. In order to assure medical-grade QoS, we firstly define the service priority of medical traffic based on their characteristics and requirements, and then we propose the enhanced channel access scheme, referred to as DIFF-CW. The proposed scheme differentiates CW (Contention Window) depending on the service priority and modifies the channel access procedure for low-priority traffic. The simulation results confirm that the DIFF-CW scheme not only assures the QoS of medical traffic but also improves the overall channel utilization.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.1
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• pp.37-44
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• 2021

The information products dramatically reduce the production costs of vertically differentiated products. Information products are also more likely to be affected by network externalities. Thus the proliferation of digital products is increasing the interests in network externality and vertical product differentiation. In step with this trend, the impact of network externalities on price competition in vertically differentiated markets has been continuously studied. Existing studies related to this topic have assumed that network externalities increase consumers' willingness to pay per unit quality. The results show that higher quality products are affected more by network externality. However, network externality is essentially a concept affected by the size of the consumer, not a concept associated with quality. In this work, unlike previous studies, we present a new market model that reflects the essential definition of network externality. Based on the proposed market model, we derive both simultaneous and sequential Nash equilibria and analyze them numerically. The main results obtained from the analysis can be summarized as follows. First, network externalities primarily increase the demand for low-quality products and have a secondary impact on the demand for high-quality products. Second, the larger the quality difference between products, the more profitable they are. It also has been shown that sequential pricing methods are more advantageous in terms of revenue than simultaneous pricing method.