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Market Segmentation of Converging New Media Advertising: The Interpretative Approach Based on Consumer Subjectivity (융합형 뉴미디어 광고의 시장세분화 연구: 소비자 주관성에 근거한 해석적 관점에서)

  • Seo, Kyoung-Jin;Hwang, Jin-Ha;Jeung, Jang-Hun;Kim, Ki-Youn
    • Journal of Internet Computing and Services
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    • v.15 no.4
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    • pp.91-102
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    • 2014
  • The purpose of this research is to perform the consumer typological study of integrated emerging digital advertisement, where IT and advertisement industry were fused, and to propose the theoretical definition about consumer characteristic which is in need for collection of related market subdivision strategy in perspective of business marketing. For this, the Q methodology, the 'subjectivity' research of qualitative perspective, which discovers new theory by interpreting subjective system of thinking, preference, opinion, and recognition of inner side of respondents, was applied and analyzed. Compared to previous quantitative research that pursues hypothesis verification, this Q methodology is not dependent on operational definition proposed by researcher but pursues for analytic study completely reflecting objective testimony of respondents. For this reason, Q study analyzes in-depth the actual consumer type, which can be found at the initial market formation stage of new service, therefore this study is applicable for theorizing the consumer character as a mean of advanced research. This study extracted thirty 'IT integrated digital advertisement type (Q sample)' from thorough literature research and interviews, and eventually discovered a total four consumer types from analyzing each Q sorting research data of 40 respondents (P sample). Moreover, by interpreting subdivided intrinsic characteristic of each group, the four types were named as 'multi-channel digital advertisement pursuit type', 'emotional advertisement pursuit type', 'new media advertisement pursuit type', and Web 2.0 advertisement pursuit type'. The analysis result of this study is being expected for its value of usage as advanced research of academic and industrial research with the emerging digital advertisement industry as a subject, and as basic research in the field of R&D, Marketing program and the field of designing the advertisement creative strategy and related policy.

Militarization and Weaponization of Outer Space in International Law

  • Kim, Han-Taek
    • The Korean Journal of Air & Space Law and Policy
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    • v.33 no.1
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    • pp.261-284
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    • 2018
  • The current international legal system does not provide a safeguard against the militarization and the weaponization of outer space. Although the term "peaceful use of outer space" in the 1967 Outer Space Treaty(OST) appears in official government statements or in multilateral space treaties, it is still without an authoritative definition in reviewing national practices. The ambiguous ban on weapons in Article IV of the OST allows countries to loophole on the deployment of other weapons other than nuclear weapons. Meanwhile "Draft Treaty on the Prevention of the Placement of Weapon in Outer Space and of the Threat or Use of Force against Outer Space Objects(PPWT)" to Conference on Disarmament (CD) commissioned by the UN General Assembly's Special Session jointly submitted by China and Russia in 2008 and later revised in 2014, attempting to define and prohibit the proliferation of weapons in outer space and provided definitions of prohibited weapons, are opposed by the US on the grounds that currently there is no arms race in outer space. Some experts support a hard law approach in which binding laws aimed at ultimately creating integrated and binding legal instruments in all aspects of the use of outer space should be adopted to regulate the military use of space. However as a temporary measure the soft law guidelines should be developed for the non liquiet, a situation where there is no applicable law. The soft law could be used to create support for the declaration of the treaties and to create international customary law. For example, the 1963 Declaration of Legal Principles Governing the Activities of States in the Exploration and Use of Outer Space that regulates the activities of the state in the exploration and use of the universe, and the 1992 Principles Relevant to the Use of Nuclear Power Sources in Outer Space will illustrated. While substantial portions of the former was codified later in the 1967 OST, the latter which, although written in somewhat mandatory terms, have been consistently complied with by states, have arguably become part of customary international law. On November 12, 1974, the General Assembly reaffirmed that the development of international law may be reflected inter alia, by declarations and resolutions of the General Assembly which may to that extent be taken into consideration by the International Court of Justice.

Numerical Analysis of Unstable Combustion Flows in Normal Injection Supersonic Combustor with a Cavity (공동이 있는 수직 분사 초음속 연소기 내의 불안정 연소유동 해석)

  • Jeong-Yeol Choi;Vigor Yang
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2003.05a
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    • pp.91-93
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    • 2003
  • A comprehensive numerical study is carried out to investigate for the understanding of the flow evolution and flame development in a supersonic combustor with normal injection of ncumally injecting hydrogen in airsupersonic flows. The formulation treats the complete conservation equations of mass, momentum, energy, and species concentration for a multi-component chemically reacting system. For the numerical simulation of supersonic combustion, multi-species Navier-Stokes equations and detailed chemistry of H2-Air is considered. It also accommodates a finite-rate chemical kinetics mechanism of hydrogen-air combustion GRI-Mech. 2.11[1], which consists of nine species and twenty-five reaction steps. Turbulence closure is achieved by means of a k-two-equation model (2). The governing equations are spatially discretized using a finite-volume approach, and temporally integrated by means of a second-order accurate implicit scheme (3-5).The supersonic combustor consists of a flat channel of 10 cm height and a fuel-injection slit of 0.1 cm width located at 10 cm downstream of the inlet. A cavity of 5 cm height and 20 cm width is installed at 15 cm downstream of the injection slit. A total of 936160 grids are used for the main-combustor flow passage, and 159161 grids for the cavity. The grids are clustered in the flow direction near the fuel injector and cavity, as well as in the vertical direction near the bottom wall. The no-slip and adiabatic conditions are assumed throughout the entire wall boundary. As a specific example, the inflow Mach number is assumed to be 3, and the temperature and pressure are 600 K and 0.1 MPa, respectively. Gaseous hydrogen at a temperature of 151.5 K is injected normal to the wall from a choked injector.A series of calculations were carried out by varying the fuel injection pressure from 0.5 to 1.5MPa. This amounts to changing the fuel mass flow rate or the overall equivalence ratio for different operating regimes. Figure 1 shows the instantaneous temperature fields in the supersonic combustor at four different conditions. The dark blue region represents the hot burned gases. At the fuel injection pressure of 0.5 MPa, the flame is stably anchored, but the flow field exhibits a high-amplitude oscillation. At the fuel injection pressure of 1.0 MPa, the Mach reflection occurs ahead of the injector. The interaction between the incoming air and the injection flow becomes much more complex, and the fuel/air mixing is strongly enhanced. The Mach reflection oscillates and results in a strong fluctuation in the combustor wall pressure. At the fuel injection pressure of 1.5MPa, the flow inside the combustor becomes nearly choked and the Mach reflection is displaced forward. The leading shock wave moves slowly toward the inlet, and eventually causes the combustor-upstart due to the thermal choking. The cavity appears to play a secondary role in driving the flow unsteadiness, in spite of its influence on the fuel/air mixing and flame evolution. Further investigation is necessary on this issue. The present study features detailed resolution of the flow and flame dynamics in the combustor, which was not typically available in most of the previous works. In particular, the oscillatory flow characteristics are captured at a scale sufficient to identify the underlying physical mechanisms. Much of the flow unsteadiness is not related to the cavity, but rather to the intrinsic unsteadiness in the flowfield, as also shown experimentally by Ben-Yakar et al. [6], The interactions between the unsteady flow and flame evolution may cause a large excursion of flow oscillation. The work appears to be the first of its kind in the numerical study of combustion oscillations in a supersonic combustor, although a similar phenomenon was previously reported experimentally. A more comprehensive discussion will be given in the final paper presented at the colloquium.

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LONGEVITY AND FAILURE ANALYSIS OF FIXED RESTORATIONS SERVICED IN KOREA (국내에서 제작된 고정성 보철물의 수명과 실패 요인 및 양상)

  • Shin Woo-Jin;Jeon Young-Sik;Lee Keun-Woo;Lee Ho-Yong;Han Dong-Hoo
    • The Journal of Korean Academy of Prosthodontics
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    • v.43 no.2
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    • pp.158-175
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    • 2005
  • Statement of problem. Every effort has been continually made to obtain objectivity in measuring the longevity of fixed restorations, such as by establishing unified judgement standard for deciding success and adopting statistical method that analyzes the data of successful and failed cases at the same time. In Korea, however desired level of development has not to be made in this field yet. Purpose. This study, adopting California Dental Association (CDA) quality evaluation system, established objective standard for deciding success, and inferred the longevity of fixed restorations and their failure analysis through adopting Kaplan-Meier survival analysis. Material and method. In order to assess the longevity of flxed restorations serviced in Korea and causes of failure, a total of 1109 individuals (aged 15-74, 716 women and 393 men loaded with 2551 unit fixed restorations, and 1934 abutments) who lived in Kyung-In Province were examined and the findings were as follows : Results. 1. Length of service of fixed restorations serviced in Korea was 6.86$\pm$0.15 yr (mean), 5.5 yr (median), and the rate of success was 65.82% in 5 year survival, and 21.15% in 10 year survival. 2. When there was patient's need for replacing old prosthetics, longevity of fixed restorations was 7.51$\pm$0.27 yr (mean), 7 yr (median), and the rate of success was 61.08% in 5 year survival, and 17.57% in 10 year survival. 3. Longevity of fixed restorations was longest in the over-sixty age group(9.21$\pm$0.66) and that of the teen age group(3.39$\pm$0.28) was shortest (p<0.05). 4. Longevity of fixed restorations of women (7.38$\pm$0.18 years) was longer than that of men (6.00$\pm$0.26) (p<0.05). 5. As for the provider factor (such as unlicensed performers, university hospitals, and private clinic), there was no statistically significant difference in longevity of fixed restorations. 6. Defective margin (34.78%). periodontal disease (12.15%), periapical involvement (11.73%), was the most frequent causes of failure and poor esthetics group showed the longest life above all (p<0.05). Actual frequent causes of failure after removing old prosthetics were defective margin, periapical involvement, periodontal disease and uncemented restoration. In 75.67% of the cases, abutment state after removing old prosthetics was good enough for loading another prosthetics. 7. There was found to have statistically significant influence between longevity of single crown (6.35$\pm$0.20 yr) and that of 3 unit fixed restorations (7.60$\pm$0.30 y) (p<0.05). In each case the most frequent cause of failure was defective margin. 8. The number of cantilever pontic, pontic/abutment ratio, oral hygiene status were found to have no statistically significant influence on longevity of fixed restorations in all groups (p>0.05). 9. Longevity of fixed restorations made of non precious metal was longest (9.60$\pm$0.40 yr) semi precious and precious trailing behind(p<0.05). 10. Group function group (37.04%) and partial group function group (44.62%) were predominant in frequency but showed no correlation between them and among different types of occlusal plane and different types of occlusal surface (p>0.05). 11. Longevity of fixed restorations was longest in the centric interference group(9.35$\pm$0.62) (p<0.05) among different types of occlusal interference. Conclusion. We found that longevity of fixed restorations serviced in Korea is affected by age, gender and type of material, and that most frequent cause of failure is defective margin. In order to assess the accurate longevity of axed restorations, unified research design. overcoming inter-observer difference and establishing the objective research items are needed. Furthermore, it is thought that prospective approach through thorough study and regular follow-ups is needed just from the start of research. Nationwide detailed studies on length of service of fixed restorations manufactured in Korea are hoped to be conducted hereafter.

Development of a Home-based Nursing Intervention, Mothering Program for Low-Birth-Weight Infants (저체중출생아를 위한 가정간호형 모성역할중재 프로그램 개발과 그 효과에 대한 연구)

  • Han, Kyung-Ja
    • Journal of Home Health Care Nursing
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    • v.8 no.1
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    • pp.5-24
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    • 2001
  • The purpose of this study was to develop a parenting intervention program and determine the efficacy of the program with low-birth weight infants and their mothers. Nine dyads for the experimental group and twelve dyads for the control group discharged from the Neonatal Intensive Care Unit of a University Hospital in Seoul were recruited for the study. For the intervention group, programmed education and support which focused on the maternal sensitivity of the infant's behavior. rearing environment. motherinfant interaction and infant care were given to each subject. Individual counseling and home visits were provided at discharge, one week after discharge. and one and three months of corrected age in every infant. Structured questionaires were administered and feeding interactions were videotaped and coded by a blinded certified observer. A Quasi-experimental design was conducted for this study. Postpartum depression, maternal self esteem. infant care burden, HOME. mother-infant interaction, and infant development were measured. Results were in favor of the intervention versus the control group. On the Beck depression inventory, intervention mothers showed decreasing trends in depressive symptom vs control mothers although, there were statistically no significant differences between the two groups at each time. The mean score of experimental group was 11.55(mild depression state) at discharge and became 8,6(normal state) at 1 month of corrected age. On the other hand, the mean score of the control group was 13.92(mild depression state) at discharge and became 14.0. Maternal self esteem in both groups improved over time. Infant care burden in both groups was also shown to increase over time. There was a significant difference between the two groups in HOME(p=.0340) at 3 months of corrected age. HOME scores of the experimental group and the control's were 31.10 and 25.58, respectively. Mothers' emotional and language responses were significantly high in the intervention group compared with the control group(p=.0155). Intervention group (53.33) showed a significantly high quality of motherinfant interaction compared with the in control group (42.80)(p =.0340). Intervention group mothers appeared have a better quality of mother-infant interaction behaviors. On the other hand, there was no statistical difference in the infant part between groups. Intervention group infants had higher trends in a general developmental quotient: although, there was no statistical difference between groups. The general developmental quotient of intervention infants was 102.56 and control's was 91.28. However, the developmental quotient of the domain of 'individuality-sociality' was higher in the intervention group infants compared with the control's(p=.0155). The concerns identified by parents revealed two domains of an infants' health management -knowledge and skills in caregiving of lowbirthweight-infants, characteristics of lowbirthweight infants, identifying a developmental milestone, coping with emergency situations and relaxation strategies of mothers from the infant care burden. Interview data with the mothers of low-birth weight infants can be used to develop intervention program contents. Limited intervention time and frequency due to time and cost limitations of this study should be modified. The intervention should be continuously implemented when low-birth weight infants become three years old. An NNNS demonstration appeared to be a very effective intervention for the mothers to improve the quality of mother-infant interactions. Therefore intervening in the mothers of low-birth weight infants as early after delivery as possible is desirable. This study has shown that home visit interventions are worthwhile for mothers only beyond the approach as an essential factor in ability of facilitating a growth fostering environment. In conclusion. the intervention program of this study was very effective in enhancing the parenting for the mothers of low-birth weight infants, resulting in health promotion of low-birth weight infants. The home-visit outreach intervention program of this study will contribute to the health delivery system in this country where there is a lack of continuous follow-up programs for low-birth weight infants after discharge from NICU, if it is activated as part of the home visit programs in community health systems.

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Participation Level in Online Knowledge Sharing: Behavioral Approach on Wikipedia (온라인 지식공유의 참여정도: 위키피디아에 대한 행태적 접근)

  • Park, Hyun Jung;Lee, Hong Joo;Kim, Jong Woo
    • Journal of Intelligence and Information Systems
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    • v.19 no.4
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    • pp.97-121
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    • 2013
  • With the growing importance of knowledge for sustainable competitive advantages and innovation in a volatile environment, many researches on knowledge sharing have been conducted. However, previous researches have mostly relied on the questionnaire survey which has inherent perceptive errors of respondents. The current research has drawn the relationship among primary participant behaviors towards the participation level in knowledge sharing, basically from online user behaviors on Wikipedia, a representative community for online knowledge collaboration. Without users' participation in knowledge sharing, knowledge collaboration for creating knowledge cannot be successful. By the way, the editing patterns of Wikipedia users are diverse, resulting in different revisiting periods for the same number of edits, and thus varying results of shared knowledge. Therefore, we illuminated the participation level of knowledge sharing from two different angles of number of edits and revisiting period. The behavioral dimensions affecting the level of participation in knowledge sharing includes the article talk for public discussion and user talk for private messaging, and community registration, which are observable on Wiki platform. Public discussion is being progressed on article talk pages arranged for exchanging ideas about each article topic. An article talk page is often divided into several sections which mainly address specific type of issues raised during the article development procedure. From the diverse opinions about the relatively trivial things such as what text, link, or images should be added or removed and how they should be restructured to the profound professional insights are shared, negotiated, and improved over the course of discussion. Wikipedia also provides personal user talk pages as a private messaging tool. On these pages, diverse personal messages such as casual greetings, stories about activities on Wikipedia, and ordinary affairs of life are exchanged. If anyone wants to communicate with another person, he or she visits the person's user talk page and leaves a message. Wikipedia articles are assessed according to seven quality grades, of which the featured article level is the highest. The dataset includes participants' behavioral data related with 2,978 articles, which have reached the featured article level, with editing histories of articles, their article talk histories, and user talk histories extracted from user talk pages for each article. The time period for analysis is from the initiation of articles until their promotion to the featured article level. The number of edits represents the total number of participation in the editing of an article, and the revisiting period is the time difference between the first and last edits. At first, the participation levels of each user category classified according to behavioral dimensions have been analyzed and compared. And then, robust regressions have been conducted on the relationships among independent variables reflecting the degree of behavioral characteristics and the dependent variable representing the participation level. Especially, through adopting a motivational theory adequate for online environment in setting up research hypotheses, this work suggests a theoretical framework for the participation level of online knowledge sharing. Consequently, this work reached the following practical behavioral results besides some theoretical implications. First, both public discussion and private messaging positively affect the participation level in knowledge sharing. Second, public discussion exerts greater influence than private messaging on the participation level. Third, a synergy effect of public discussion and private messaging on the number of edits was found, whereas a pretty weak negative interaction effect of them on the revisiting period was observed. Fourth, community registration has a significant impact on the revisiting period, whereas being insignificant on the number of edits. Fifth, when it comes to the relation generated from private messaging, the frequency or depth of relation is shown to be more critical than the scope of relation for the participation level.

A Method for Evaluating News Value based on Supply and Demand of Information Using Text Analysis (텍스트 분석을 활용한 정보의 수요 공급 기반 뉴스 가치 평가 방안)

  • Lee, Donghoon;Choi, Hochang;Kim, Namgyu
    • Journal of Intelligence and Information Systems
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    • v.22 no.4
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    • pp.45-67
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    • 2016
  • Given the recent development of smart devices, users are producing, sharing, and acquiring a variety of information via the Internet and social network services (SNSs). Because users tend to use multiple media simultaneously according to their goals and preferences, domestic SNS users use around 2.09 media concurrently on average. Since the information provided by such media is usually textually represented, recent studies have been actively conducting textual analysis in order to understand users more deeply. Earlier studies using textual analysis focused on analyzing a document's contents without substantive consideration of the diverse characteristics of the source medium. However, current studies argue that analytical and interpretive approaches should be applied differently according to the characteristics of a document's source. Documents can be classified into the following types: informative documents for delivering information, expressive documents for expressing emotions and aesthetics, operational documents for inducing the recipient's behavior, and audiovisual media documents for supplementing the above three functions through images and music. Further, documents can be classified according to their contents, which comprise facts, concepts, procedures, principles, rules, stories, opinions, and descriptions. Documents have unique characteristics according to the source media by which they are distributed. In terms of newspapers, only highly trained people tend to write articles for public dissemination. In contrast, with SNSs, various types of users can freely write any message and such messages are distributed in an unpredictable way. Again, in the case of newspapers, each article exists independently and does not tend to have any relation to other articles. However, messages (original tweets) on Twitter, for example, are highly organized and regularly duplicated and repeated through replies and retweets. There have been many studies focusing on the different characteristics between newspapers and SNSs. However, it is difficult to find a study that focuses on the difference between the two media from the perspective of supply and demand. We can regard the articles of newspapers as a kind of information supply, whereas messages on various SNSs represent a demand for information. By investigating traditional newspapers and SNSs from the perspective of supply and demand of information, we can explore and explain the information dilemma more clearly. For example, there may be superfluous issues that are heavily reported in newspaper articles despite the fact that users seldom have much interest in these issues. Such overproduced information is not only a waste of media resources but also makes it difficult to find valuable, in-demand information. Further, some issues that are covered by only a few newspapers may be of high interest to SNS users. To alleviate the deleterious effects of information asymmetries, it is necessary to analyze the supply and demand of each information source and, accordingly, provide information flexibly. Such an approach would allow the value of information to be explored and approximated on the basis of the supply-demand balance. Conceptually, this is very similar to the price of goods or services being determined by the supply-demand relationship. Adopting this concept, media companies could focus on the production of highly in-demand issues that are in short supply. In this study, we selected Internet news sites and Twitter as representative media for investigating information supply and demand, respectively. We present the notion of News Value Index (NVI), which evaluates the value of news information in terms of the magnitude of Twitter messages associated with it. In addition, we visualize the change of information value over time using the NVI. We conducted an analysis using 387,014 news articles and 31,674,795 Twitter messages. The analysis results revealed interesting patterns: most issues show lower NVI than average of the whole issue, whereas a few issues show steadily higher NVI than the average.

Continuous Wet Oxidation of TCE over Supported Metal Oxide Catalysts (금속산화물 담지촉매상에서 연속 습식 TCE 분해반응)

  • Kim, Moon Hyeon;Choo, Kwang-Ho
    • Korean Chemical Engineering Research
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    • v.43 no.2
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    • pp.206-214
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    • 2005
  • Heterogeneously-catalyzed oxidation of aqueous phase trichloroethylene (TCE) over supported metal oxides has been conducted to establish an approach to eliminate ppm levels of organic compounds in water. A continuous flow reactor system was designed to effect predominant reaction parameters in determining catalytic activity of the catalysts for wet TCE decomposition as a model reaction. 5 wt.% $CoO_x/TiO_2$ catalyst exhibited a transient period in activity vs. on-stream time behavior, suggesting that the surface structure of the $CoO_x$ might be altered with on-stream hours; regardless, it is probable to be the most promising catalyst. Not only could the bare support be inactive for the wet decomposition reaction at $36^{\circ}C$, but no TCE removal also occurred by the process of adsorption on $TiO_2$ surface. The catalytic activity was independent of all particle sizes used, thereby representing no mass transfer limitation in intraparticle diffusion. Very low TCE conversion appeared for $TiO_2$-supported $NiO_x$ and $CrO_x$ catalysts. Wet oxidation performance of supported Cu and Fe catalysts, obtained through an incipient wetness and ion exchange technique, was dependent primarily on the kinds of the metal oxides, in addition to the acidic solid supports and the preparation routes. 5 wt.% $FeO_x/TiO_2$ catalyst gave no activity in the oxidation reaction at $36^{\circ}C$, while 1.2 wt.% Fe-MFI was active for the wet decomposition depending on time on-stream. The noticeable difference in activity of the both catalysts suggests that the Fe oxidation states involved to catalytic redox cycle during the course of reaction play a significant role in catalyzing the wet decomposition as well as in maintaining the time on-stream activity. Based on the results of different $CoO_x$ loadings and reaction temperatures for the decomposition reaction at $36^{\circ}C$ with $CoO_x/TiO_2$, the catalyst possessed an optimal $CoO_x$ amount at which higher reaction temperatures facilitated the catalytic TCE conversion. Small amounts of the active ingredient could be dissolved by acidic leaching but such a process gave no appreciable activity loss of the $CoO_x$ catalyst.

A New Approach to Mobile Device Design - focused on the Communication Tool & it's GUI for Office Workers in the Near Future - (모바일 기기 디자인의 새로운 접근 - 근 미래 작업환경에서의 커뮤니케이션 도구 디자인과 GUI 연구를 중심으로 -)

  • Yang, Sung-Ho
    • Archives of design research
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    • v.19 no.2 s.64
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    • pp.31-42
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    • 2006
  • This study originates from the following critical mind; what will the office of the future be like? and what technology will we rely upon most to communicate with colleagues or to access business information. In the office environment today, new technology has compelled new work paradigm and has greatly affected the capabilities of the individual to work in a more productive and efficient manner. However, even though new computer technology has changed the business world so rapidly, it is very difficult to see the changes that have been taken place. As an aim of the study, creating a mobile tool for office workers that successfully supports their work and communication was explored, and this study explored future work environment with a 5 years technological and social perspective. As a result of this study, the bON brings new visions to the mobile professionals via various interfaces. The bON, a mobile device, is both a system of work and of communication for office workers. The bON, as an integrated tool for working and communicating, forms the basis for a mobile information gateway that is equally capable of functioning as a mobile desk. The basic underlying idea is that all formal meeting places and hallways in the office are equipped with large wall-mounted screens. The bON collaborates with these media in various ways to enhance productivity and efficiency. The main challenge for the bON to enhance both mobility and quality of information is using new technology including bendable and flexible display and soft material display and sensors. To answer for the strong needs for mobility, the whole size of the device is fairly small while the screen is rolled inside the device. For Graphical User Interface, moreover, a new technique called Multi-layering Interface was adopted to stretch user's visual limits and suggests new direction in designing mobile device, equipped with small size display.

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Bankruptcy Type Prediction Using A Hybrid Artificial Neural Networks Model (하이브리드 인공신경망 모형을 이용한 부도 유형 예측)

  • Jo, Nam-ok;Kim, Hyun-jung;Shin, Kyung-shik
    • Journal of Intelligence and Information Systems
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    • v.21 no.3
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    • pp.79-99
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    • 2015
  • The prediction of bankruptcy has been extensively studied in the accounting and finance field. It can have an important impact on lending decisions and the profitability of financial institutions in terms of risk management. Many researchers have focused on constructing a more robust bankruptcy prediction model. Early studies primarily used statistical techniques such as multiple discriminant analysis (MDA) and logit analysis for bankruptcy prediction. However, many studies have demonstrated that artificial intelligence (AI) approaches, such as artificial neural networks (ANN), decision trees, case-based reasoning (CBR), and support vector machine (SVM), have been outperforming statistical techniques since 1990s for business classification problems because statistical methods have some rigid assumptions in their application. In previous studies on corporate bankruptcy, many researchers have focused on developing a bankruptcy prediction model using financial ratios. However, there are few studies that suggest the specific types of bankruptcy. Previous bankruptcy prediction models have generally been interested in predicting whether or not firms will become bankrupt. Most of the studies on bankruptcy types have focused on reviewing the previous literature or performing a case study. Thus, this study develops a model using data mining techniques for predicting the specific types of bankruptcy as well as the occurrence of bankruptcy in Korean small- and medium-sized construction firms in terms of profitability, stability, and activity index. Thus, firms will be able to prevent it from occurring in advance. We propose a hybrid approach using two artificial neural networks (ANNs) for the prediction of bankruptcy types. The first is a back-propagation neural network (BPN) model using supervised learning for bankruptcy prediction and the second is a self-organizing map (SOM) model using unsupervised learning to classify bankruptcy data into several types. Based on the constructed model, we predict the bankruptcy of companies by applying the BPN model to a validation set that was not utilized in the development of the model. This allows for identifying the specific types of bankruptcy by using bankruptcy data predicted by the BPN model. We calculated the average of selected input variables through statistical test for each cluster to interpret characteristics of the derived clusters in the SOM model. Each cluster represents bankruptcy type classified through data of bankruptcy firms, and input variables indicate financial ratios in interpreting the meaning of each cluster. The experimental result shows that each of five bankruptcy types has different characteristics according to financial ratios. Type 1 (severe bankruptcy) has inferior financial statements except for EBITDA (earnings before interest, taxes, depreciation, and amortization) to sales based on the clustering results. Type 2 (lack of stability) has a low quick ratio, low stockholder's equity to total assets, and high total borrowings to total assets. Type 3 (lack of activity) has a slightly low total asset turnover and fixed asset turnover. Type 4 (lack of profitability) has low retained earnings to total assets and EBITDA to sales which represent the indices of profitability. Type 5 (recoverable bankruptcy) includes firms that have a relatively good financial condition as compared to other bankruptcy types even though they are bankrupt. Based on the findings, researchers and practitioners engaged in the credit evaluation field can obtain more useful information about the types of corporate bankruptcy. In this paper, we utilized the financial ratios of firms to classify bankruptcy types. It is important to select the input variables that correctly predict bankruptcy and meaningfully classify the type of bankruptcy. In a further study, we will include non-financial factors such as size, industry, and age of the firms. Thus, we can obtain realistic clustering results for bankruptcy types by combining qualitative factors and reflecting the domain knowledge of experts.