• Journal of the Korean Mathematical Society
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• v.57 no.1
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• pp.171-194
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• 2020

For a nonautonomous dynamics defined by a sequence of bounded linear operators on a Banach space, we give a characterization of the existence of an exponential dichotomy with respect to a sequence of norms in terms of the invertibility of a certain linear operator between general admissible spaces. This notion of an exponential dichotomy contains as very special cases the notions of uniform, nonuniform and tempered exponential dichotomies. As applications, we detail the consequences of our results for the class of tempered exponential dichotomies, which are ubiquitous in the context of ergodic theory, and we show that the notion of an exponential dichotomy under sufficiently small parameterized perturbations persists and that their stable and unstable spaces are as regular as the perturbation.

• Proceedings of the Korean Society for Quality Management Conference
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• 2009.10a
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• pp.176-181
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• 2009

Social networking service (SNS), which is based on the "six degree separation" theory, has gained its popularity in recent years. SNS creates a new way for maintaining relationship and sharing information over the virtual space. As a major branch, campus SNS provides a new platform for student to study as well as build and maintain inter-personal relationships. The highly realness of personal information and relatively strong group cohesion of campus SNS has turned it into an inevitable tool in students' daily life. The rapid growth of SNS in campus is creating huge academic and commercial benefits. However, little comprehensive research reveals what are determinant factors in driving students' intention to participate in campus SNS. In this paper, we conceptualize the participation of campus SNS as a social behavior and evaluate the impact made by social factors such as subjective norms and identity, as well as the impact of perceived reality and playfulness through an extended technology acceptance model.

• Journal of electromagnetic engineering and science
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• v.11 no.2
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• pp.71-75
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• 2011

The sum-rate maximization rule can find an optimal user set that maximizes the sum capacity in multiple input multiple output (MIMO) broadcast channels (BCs), but the search space for finding the optimal user set becomes prohibitively large as the number of users increases. The proposed algorithm selects a user set of the largest effective channel norms based on statistical channel state information (CSI) for reducing the computational complexity, and uses Tomlinson-Harashima precoding (THP) for minimizing the interference between selected users in time-varying MIMO BCs.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.5
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• pp.69-78
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• 2005

It is crucial to compute the Euclidean distance between two vectors efficiently in high dimensional space for multimedia information retrieval. In this paper, we propose an effective method for approximating the Euclidean distance between two high-dimensional vectors. For this approximation, a previous method, which simply employs norms of two vectors, has been proposed. This method, however, ignores the angle between two vectors in approximation, and thus suffers from large approximation errors. Our method introduces an additional vector called a reference vector for estimating the angle between the two vectors, and approximates the Euclidean distance accurately by using the estimated angle. This makes the approximation errors reduced significantly compared with the previous method. Also, we formally prove that the value approximated by our method is always smaller than the actual Euclidean distance. This implies that our method does not incur any false dismissal in multimedia information retrieval. Finally, we verify the superiority of the proposed method via performance evaluation with extensive experiments.

• Korean Journal of Remote Sensing
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• v.35 no.2
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• pp.241-250
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• 2019

The current U.S. remote sensing act was made in 1992 and has been criticized for being outdated and inappropriate in view of the modern technological development. In order to enhance the American competitiveness and leadership in the world, President Trump announced Space Policy Directive (SPD) - 2 on May 24, which is designed to modernize the regulations related to commercial space activities including private remote sensing system operations. It should be noted that the regulatory reform efforts are made within broader terms of the National Security Strategy on Dec. 17, 2017, pursuing the enhancement of national security and economic prosperity as well. A legislative support in Congress has also been added to the Administration's efforts. The proposed regulatory reform on the licensing of commercial remote sensing system operations outlines the features of lessening administrative burden on applicants by simplifying the overall application process and of limiting the operations only when there is an impact upon the national security with clear and convincing evidence. But, due to a different regulatory system of each country, such a movement to expand an individual's freedom to explore and utilize outer space may result in an international dispute or a violation of international obligations, so there should be a merit in paying attention to the U.S. commercial remote sensing regulatory reform, and it is desirable to establish international norms as flexible and appropriate to the level of space technology and space industry.

• The Korean Journal of Air & Space Law and Policy
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• v.29 no.2
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• pp.205-237
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• 2014

Last 50 years there were a lot of space subjects launched by space activities of many states and these activities also had created tremendous, significant space debris contaminating the environment of outer space. The large number of space debris which are surrounding the earth have the serious possibilities of destroying a satellite or causing huge threat to the space vehicles. For example, Chinese anti-satellite missile test was conducted by China on January 11, 2007. As a consequence a Chinese weather satellite was destroyed by a kinetic kill vehicle traveling with a speed of 8 km/s in the opposite direction. Anti-satellite missile tests like this,contribute to the formation of enormous orbital space debris which can remain in orbit for many years and could interfere with future space activity (Kessler Syndrome). The test is the largest recorded creation of space debris in history with at least 2,317 pieces of trackable size (golf ball size and larger) and an estimated 150,000 debris particles and more. Several nations responded negatively to the test and highlighted the serious consequences of engaging in the militarization of space. The timing and occasion aroused the suspicion of its demonstration of anti-satellite (ASAT) capabilities following the Chinese test of an ASAT system in 2007 destroying a satellite but creating significant space debris. Therefore this breakup seemed to serve as a momentum of the UN Space Debris Mitigation Guidelines and the background of the EU initiatives for the International Code of Conduct for Outer Space Activities. The UN Space Debris Mitigation Guidelines thus adopted contain many technical elements that all the States involved in the outer space activities are expected to observe to produce least space debris from the moment of design of their launchers and satellites until the end of satellite life. Although the norms are on the voluntary basis which is normal in the current international space law environment where any attempt to formulate binding international rules has to face opposition and sometimes unnecessary screening from many corners of numerous countries. Nevertheless, because of common concerns of space-faring countries, the Guidelines could be adopted smoothly and are believed faithfully followed by most countries. It is a rare success story of international cooperation in the area of outer space. The EU has proposed an International Code of Conduct for Outer Space Activities as a transparency and confidence-building measure. It is designed to enhance the safety, security and sustainability of activities in outer space. The purpose of the Code to reduce the space debris, to allow exchange of the information on the space activities, and to protect the space objects through safety and security. Of the space issues, the space debris reduction and the space traffic management require some urgent attention. But the current legal instruments of the outer space do not have any binding rules to be applied thereto despite the incresing activities on the outer space. We need to start somewhere sometime soon before it's too late with the chaotic situation. In this article, with a view point of this problem, focused on the the Chinese test of an ASAT system in 2007 destroying a satellite but creating significant space debris and tried to analyse the issues of space debris reduction.

• Journal of the Korean Geographical Society
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• v.42 no.4
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• pp.560-581
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• 2007

The purpose of this paper is to present a conceptual framework and a stage of development of trust building and to study the factors affecting on the trust building in economics space. Conceptual framework on trust building in economics space is combined of in the three approaches. The macro(structural and institutional) approach includes normative and regulative factors(laws, norms), and positionality in social and economic systems(beliefs, political ideologies, institutions). The meso(intersubjective) approach contains the personal fronts(expressive factors, social cues, significant symbols) and settings(physical space, intermediary such as technologies & knowledges). The micro(subjective) approach comprises the willingness(internalization of value) and calculation(risk and uncertainties analysis) of economic actors. According to sustainable cooperation among economic actors, trust building to the macro(structural and institutional) level, the meso(intersubjective) level, and the micro(subjective) level develop by stages. The factors such as long-term and repeated interaction, information sharing and reciprocity, interdependence and asset specificity, uncertainty, proximity, and culture & norm of corporate and formal institution are determinants on the trust building across economic actors in economic space.

• Journal of the Chungcheong Mathematical Society
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• v.19 no.4
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• pp.325-334
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• 2006

For $f{\in}L^2(B,d{\nu})$, ${\parallel}f{\parallel}_{BMO}=\widetilde{{\mid}f{\mid}^2}(z)-{\mid}{\tilde{f}}(z){\mid}^2$. For f continuous on B, ${\parallel}f{\parallel}_{BO}=sup\{w(f)(z):z{\in}B\}$ where $w(f)(z)=sup\{{\mid}f(z)-f(w){\mid}:{\beta}(z,w){\leq}1\}$. In this paper, we will show that if $f{\in}BMO$, then ${\parallel}f{\parallel}_{BO}{\leq}M{\parallel}f{\parallel}_{BMO}$. We will also show that if $f{\in}BO$, then ${\parallel}f{\parallel}_{BMO}{\leq}M{\parallel}f{\parallel}_{BO}^2$. A homomorphic function $f:B{\rightarrow}{\mathbb{C}}$ is called a Bloch function ($f{\in}{\mathcal{B}}$) if ${\parallel}f{\parallel}_{\mathcal{B}}=sup_{z{\in}B}\;Qf(z)$<${\infty}$. In this paper, we will show that if $f{\in}{\mathcal{B}}$, then ${\parallel}f{\parallel}_{BO}{\leq}{\parallel}f{\parallel}_{\mathcal{B}}$. We will also show that if $f{\in}BMO$ and f is holomorphic, then ${\parallel}f{\parallel}_{\mathcal{B}}^2{\leq}M{\parallel}f{\parallel}_{BMO}$.

• The Research Journal of the Costume Culture
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• v.26 no.4
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• pp.583-597
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• 2018

The purpose of this study is to classify and analyze the deconstruction phenomena expressed in contemporary knit fashion design, and to analyze the inner meaning of deconstruction based on certain characteristics. As a method of study, literature data for theoretical backgrounds, prior studies, and internet data were analyzed. The scope of this study was restricted to knitwear published in the world's four major collections (Milan, Paris, New York and London) from 2014 F/W to 2018 S/S. Based on prior studies, four concepts of deconstruction were derived: "$Diff{\acute{e}}reance$", "Intertextuality", "Intermeaning of Meaning", "Dis De Phenomenon". The results of the study were as follows: first, "$Diff{\acute{e}}reance$" refers to a transcendence of time and space. These expressions are discursive, unrealistic, and convey freedom through intent that deviates from rules and norms. Second, "Intertextuality" indicates a mixture of different texts, such as styles, materials, and items. These expressions deliver novelty with amusement, and can be entertaining depending on audience expectations. Third, "Intermeaning of Meaning" is accidental category - depending on how the wearer wears the clothing. -; accordingly, free and spontaneous creativity is an emerging trend in fashion. Fourth, the clothing was expressed in deformed and distorted form by the construction and destruction of the structure, a technique we describe as the "Dis De Phenomenon". In this concept, the sense of free design of young emotion appears along with the sense of purity and shock due to intentional inconsistency.

• The Korean Journal of Archival Studies
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• no.10
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• pp.65-111
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• 2004

In the modern society, Archives are an available subject to the people of a nation and it is indispensable to build and appropriate access environment in order to connect the users and the registered records stored in the facilities. Specially, the Closed Shelves Access system, based on the notion of "a Policy of Archives Preservation", needs to be fully equipped with an access environment more adequate to its necessities. Hence, this study has analyzed all sorts of environments-institutional, organizational, human, physical and intellectual- from a general perspective in order to activate users to read the archives and based on this, the objective of the research is in proposing a program that effectively provides archives to the users and provides the basis for putting into practice an active access environment. The use of archives is the fountainhead in order to preserve archives. By using the archives, the meaning of preserving them is maximized. Whether these archives may be used or not will depend on the quality of information and the advancement of the access environment. Therefore, in order to motivate users to access the archives, first of all the facilities and the archivists must establish norms regarding the access, based on statutes and once they have been settled, they should provide other changes such as ; the development and fixation in the organization's structure, the education of specialized human labor, the expansion of physical space and the facilities and diverse positive services.