• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.3
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• pp.444-453
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• 2007

This paper deals with a powerful countermeasure for power quality problems caused by the operation of electrical arc furnace in bulk power systems. The rapid active load fluctuations of electrical arc furnace could produce several problems such as voltage flicker and active power oscillations. The typical methods using only the reactive power compensation have their own limitation in solving the power quality problems caused by active load variations. The coordination of both active and reactive power compensation is required to solve the power quality problems. This paper focuses on the impacts and the dynamic phenomena caused by the active load fluctuation. This paper proposes the optimal algorithm for the active power compensation based on the function of 1(n ratio and the concepts for the active power compensation. The results from a case study show that the proposed methods can be a practical tool for the power quality problems in power systems.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.1
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• pp.5-10
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• 2015

D2D (Device-to-Device) communication underlaying LTE-advanced networks is a promising technology to improve the system capacity and spectral efficiency. By sharing the same radio resources with cellular user equipments, D2D communications can significantly enhance the overall spectral efficiency. However, it may cause interference between D2D link and cellular link. Careful resource allocation and interference coordination between cellular and D2D communications are very important and need to be properly handled. This paper proposes a radio resource allocation scheme based on FFFR (Flexible Fractional Frequency Reuse) for D2D communication underlaying cellular networks. The base station selects randomly resource blocks assigned to cellular users, and reuses them for a D2D pair. Through simulations, we have confirmed that the proposed scheme improves the system throughput, reduces the computational complexity, and mitigates the interference of D2D link and cellular link.

• Journal of KIISE:Software and Applications
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• v.41 no.8
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• pp.569-579
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• 2014

In a tactical-edge environment, where multiple weapon resources are coordinated together via services, it is essential to make an efficient binding between an abstract service and a resource that are needed to execute composite services for accomplishing a given mission. However, the tactical network that is used in military operation has low bandwidth and a high rate of packet loss. Therefore, communication overhead between services must be minimized to execute composite services in a stable manner in the tactical network. In addition, a tactical-edge environment changes dynamically, and it affects the connectivity and bandwidth of the tactical network. To deal with these characteristics of the tactical network we propose two service-resource reallocation methods which minimize the communication overhead between service gateways and effectively manage neutralization of gateways during distributed service coordination. We compared the effectiveness of these two - methods in terms of total communication overhead between service gateways and resource-allocation similarity between the initial resource allocation and the reallocation result.

• Ocean and Polar Research
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• v.27 no.2
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• pp.171-179
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• 2005

Korea has many underwater cultural heritages within the east, west and south seas surrounding the Peninsula that indicate historically important sealanes for trade and transportation. As these underwater cultural heritages are the objects of despoilment because of their relatively easy access through modern technology, their often high historical and priceless value demands strong protection similar to or better than the land cultural properties. Currently, Korea does not have any concrete laws or regulations for the protection of underwater cultural heritages. Thus, these heritages iu, somewhat temporary and inappropriately subjected to laws and regulations relating to provisions of individual Laws concerning protection of cultural properties act, and statute of excavation of material fir buried national property, lost articles act etc.. Internationally, the UNESCO Convention on the Protection of the Underwater Cultural Heritage was adopted but not yet entered into force. Therefore, the protection of underwater cultural heritage has become an urgent matter. In this regard, this article's main purpose is to provide recommendations for improving direction of legal regime and policy for protecting our underwater cultural heritages. These legal regimes need provisions for definition of the underwater cultural heritage, scope of application, ownerships, jurisdictions and protection measures. And suggestions are provided in regard to policies for the protection of underwater cultural heritages that may improve organization and cooperation among concerned ministries and agencies, compensation system, restrictions for excavation of underwater relics, efficiency of survey of underwater surface and information system.

• Journal of the Korea Fashion and Costume Design Association
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• v.11 no.1
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• pp.155-167
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• 2009

This study reviewed the basic principle of "Maximalism" fashion and analyzed the properties of fashion types with found the frequencies of various styles and design factors of "Maximalism" fashion in collection. The limits of this study is from 2001, s/s, maximalism was embossed in a modem fashion, to 2007, f/w, and collected the fashion collection pictures from www.samsungdesign.net and www.style.com. The results of this study are as follows. First, the most frequent style of "Maximalism" design showed in International fashion collection was "exaggerated style." Second, the design factors of "Maximalism" fashion were also examined. In case of silhouette, "hourglass silhouette" was the most frequent silhouette. In case of pattern, "solid" color was the most frequently used. In case of materials, the soft materials were the most frequently used. Third, the frequencies of design factors of maximalism by presentation types was compared and analyzed. In case of expansion, "bulk silhouette" was the most frequent silhouette to be appeared, and about multi-ethnic, futurelism, and elegance, "hourglass silhouette" was frequent appeared. In case of pattern, "solid" color was the most frequently used in all types. In case of materials, the hard materials were the most frequently used in expansion, multi-ethnic and futurelism. "Maximalism" fashion which is most splendid trend would grow up rapidly in the modem fashion market and influence on the other fashion trend in our every day life. Consequently, this research can be referred as practical information in fashion marketing and it will contribute to the future fashion research as well.

• Journal of Fashion Business
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• v.10 no.2
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• pp.194-206
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• 2006

With the change of social paradigm, the number of child care facilities is increasing and, accordingly, demand for sportswear for preschool children is also growing. Considering this trend, the present study purposed to subdivide the preschooler' sportswear market, which is currently using uniform design, and diversify the images of preschoolers' sportswear utilizing information on preschoolers' sportswear market, to produce high-quality sportswear of reasonable price, and to induce the development of various materials and designs. The results of this study are as follows. First, according to the result of paired t-test on the current image of preschoolers' sportswear and its future image to be promoted, among 22 items of sportswear image, the scores of comfortable and active images were highest. According to the results of factor analysis, five factors were identified, and kindergarten directors gave the highest score to plain image for preschoolers' sportswear and the lowest score to elegance image. This suggests that there should be active and diverse approaches to sportswear design. When the mean score of factors was compared among preschoolers' sportswear image to be promoted in the future, high-class elegant image got the highest score and was followed by functional image. In addition, lively and neat image got the lowest score. Second, when we analyzed the correlations between the five factors of image identified through factor analysis and three groups formed through cluster analysis in order to classify buyers based on the current images of preschoolers' sportswear and future images to be promoted, kindergarten directors were found to emphasize functional image currently in selecting sportswear for their children but to promote elegant image for future sportswear.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.2
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• pp.156-173
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• 2004

Business process should support the execution of collaboration process with agility and flexibility through the integration of enterprise inner or outer applications and human resources from the collaborative workflow view. Although the dependency of enterprise activities to the automated system has been increasing, human role is as important as ever. In the workflow modelling this human role is emphasized and the structure to control human error by analysing decision-making itself is needed. Also, through the collaboration of activities agile and effective communication should be constructed, eventually by the combination and coordination of activities to the aimed process the product quality should be improved. This paper classifies human errors can be occurred in collaborative workflow by applying GEMS(Generic Error Modelling System) to control them, and suggests human error control method through hybrid based modelling as well. On this base collaborative workflow modeling tool is designed and implemented. Using this modelling methodology it is possible to workflow modeling could be supported considering human characteristics has a tendency of human error to be controlled.

• Journal of Communications and Networks
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• v.11 no.5
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• pp.518-528
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• 2009

IEEE 802.11 wireless local area network (WLAN) has become the prevailing solution for wireless Internet access while transport control protocol (TCP) is the dominant transport-layer protocol in the Internet. It is known that, in an infrastructure-based WLAN with multiple stations carrying long-lived TCP flows, the number of TCP stations that are actively contending to access the wireless channel remains very small. Hence, the aggregate TCP throughput is basically independent of the total number of TCP stations. This phenomenon is due to the closed-loop nature of TCP flow control and the bottleneck downlink (i.e., access point-to-station) transmissions in infrastructure-based WLANs. In this paper, we develop a comprehensive analytical model to study TCP dynamics in infrastructure-based 802.11 WLANs. We calculate the average number of active TCP stations and the aggregate TCP throughput using our model for given total number of TCP stations and the maximum TCP receive window size. We find out that the default minimum contention window sizes specified in the standards (i.e., 31 and 15 for 802.11b and 802.11a, respectively) are not optimal in terms of TCP throughput maximization. Via ns-2 simulation, we verify the correctness of our analytical model and study the effects of some of the simplifying assumptions employed in the model. Simulation results show that our model is reasonably accurate, particularly when the wireline delay is small and/or the packet loss rate is low.

• The Korean Journal of Ceramics
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• v.4 no.4
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• pp.323-330
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• 1998

Mixed oxide compounds of potential usefulness for fibre coatings (hexagonal celsian, $BaAl_2Si_2O_8$ and lanthanum hexaluminate, $LaAl_{11}O_{18}$) or for matrix materials (yttrium aluminium garnet, $Y_3Al_5O_{12}$) were prepared by hybrid sol-gel synthesis and their thermal crystallisation was monitored by thermal analysis, X-ray diffraction and multinuclear solid state MAS NMR. All the gels convert to the crystalline phase below about $12200^{\circ}C$, via amorphous intermediates in which the Al shows and NMR resonance at 36-38 ppm sometimes ascribed to Al in 5-fold coordination. Additional information about the structural changes during thermal treatment was provided by $^{29}Si$, $^{137}Ba$ and $^{89}Y$ MAS NMR spectroscopy, showing that the feldspar framework of celsian begins to be established by about $500^{\circ}C$ but the Ba is still moving into its polyhedral lattice sites about $400^{\circ}C$ after the sluggish onset of crystallization. Lanthanum hexaluminate and YAG crystallise sharply at 1230 and $930^{\circ}C$ respectively, the former via $\gamma-Al_2O_3$, the latter via $YAlO_3$. Yttrium moves into the garnet lattice sites less than $100^{\circ}C$ after crystallisation.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.32 no.4 s.59
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• pp.269-282
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• 2006

In this study, we tried to scrutinize the status and problems of domestic cosmetics industry. On the basis of theoretical study, we examined the strategic marketing skill and tactics of foreign products to devise a strategy for domestic cosmetics with the help of marketing mix of foreign competitors: so to say 4 Ps. The core of the empirical research is hereby the effect of consumers' behavior. The conclusion of the research can be summarized as following: the most important problem of domestic cosmetics industry is the poor brand power. It has been confirmed that the consumer needs are various and dynamic. Analysis of 4 Ps of marketing factors of foreign goods shows this very clearly. Consumers tend to rely upon the brand name of the product rather than the quality, when they don't have enough information or knowledge on the product. This conclusion teaches us to make an effective strategy of marketing. It is brand power and brand cultivating. This study may give domestic marketers a motive to predict the future and succeed in existence and prosperity.