• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.6C
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• pp.476-482
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• 2012

In this paper, we analyze and compare several co-channel interference mitigation algorithms for WBAN application in 2.4 GHz ISM frequency bands. ML (Maximum Likelihood), OC (Optimal Combining) and MMSE (Minimum Mean Square Error) has been considered for the possible techniques for interference cancellation in view of the trade off between the performance and the complexity of implementation. Based on the channel model of IEEE 802.15.6 standard, simulation results show that ML and OC attains the lower BER performance than that of MMSE if we assume the perfect channel estimation. But, ML and OC have the additional requirement of implementation for his own and other users's channel estimation process, hence, besides the BER performance, the complexity of implementation and the sensitivity to channel estimation error should be considered since it requires the simple and small sized equipment for WBAN system application. In addition, the gap of detection BER performance between ML, OC and MMSE is much decreased under the imperfect channel estimation if we adopt real channel estimation process, therefore, in order to apply to WBAN system, the trade off between the BER performance and complexity of implemetation should be seriously considered to decide the best co-channel interference cancellation for WBAN system application.

• Korean Journal of Construction Engineering and Management
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• v.18 no.3
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• pp.74-83
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• 2017

The recently introduced public rental housing REITs was just different the business structure from the existing public rental housing system and the basic supply system is the same. So the ownership conversion for public house over 10 years rental duration is possible after half of the obligated rental duration according to the agreement between lessor and lessee. However rental business operators are likely to have a negative attitude to the early ownership conversion because of less expected profit. Thus, there is a need for an analysis of proper early ownership conversion moment that can achieve public purposes while ensuring the profitability of public rental housing REITs. In this study, the characteristics of the ownership conversion rights that can lessee to exercise considered to be options. Also the nature of 'REITs', 'public rental housing REITs' is considered to be affected by the macroeconomic variables. Thus, this study analyzed the value for ownership conversion in the public rental housing REITs according to real option scenarios reflecting macroeconomic variables. As a result, according to the change of the variation rate of the macroeconomic variables, it was found that with adjustable early ownership conversion time using the DCF(Discounted Cash Flow) model. Therefore, it is possible to ensure profitability of early ownership conversion by predicting the variation of variables.

• Management & Information Systems Review
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• v.35 no.2
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• pp.167-183
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• 2016

This study has recognized easy payment service as one of the new types of application of information and communication technologies and proposed a modified acceptance intention model by adding perceived risk factor based on the unified theory of acceptance and use of technology(UTAUT) and then explored those variables that effect the acceptance intention of consumers. The results of this study can be summarized as the followings. First, expectation on the efforts, social impact have positive effect on the acceptance intention and perceived risk has negative effect on the acceptance intention but expectation on the efforts and promotion condition were found to have no effect on the acceptance intention. Second, among the factors suggested, social impact was found to have more effect of causing the acceptance intention of users than expectation on the efforts and perceived risk. Third, it was found that there is a significant association between the acceptance intention and use behavior of users of easy payment service. This means that, as was reviewed in the preceding researches, the acceptance intention affects actual acceptance behavior of users either directly or indirectly. Fourth, even though innovation resistance has regulation effect on the relationship between expectation on efforts or social impact and acceptance intention, it was found to have no regulation effect on the relationship between perceived risk and acceptance intention.

• Geophysics and Geophysical Exploration
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• v.11 no.2
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• pp.116-126
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• 2008

In gas hydrate survey, seismic amplitude and frequency characteristics play a very important role in determining whether gas hydrate exists. According to the variation of source frequency and scatterer size, we study seismic amplitude characteristics using elastic modeling applied at staggered grids. Generally speaking, scattering occurs in proportion to the square of source frequency and the scatterer volume, which has an effect on seismic amplitude. The higher source frequency is, the more scattering occurs in gas hydrate bearing zone. Therefore, BSR is hardly observed in high frequencies. On the other side, amplitude blanking zone and BSR is clearly observed in lower frequencies although the resolution is poor as a whole. Seismic reflections traveling through free-gas layer below gas hydrate bearing zone decay so severely a high frequency component that a low frequency term is dominant. Amplitude anomaly of BSR result from high acoustic impedance contrast due to free-gas, which is a very crucial factor to estimate gas hydrate bearing zone. Seismic frequency analysis is carried out using wavelet transform method that frequency component could be decomposed with time variation. In application of wavelet transform to the seismic physical experiments data, we can observe that reflections traveling through air layer, which corresponds to the free-gas layer, decay a high frequency component.

• Journal of Service Research and Studies
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• v.9 no.1
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• pp.1-16
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• 2019

This study analyzed Korean representative ideology to establish a service philosophy. As a follow - up study of the service philosophy consistency study of the Korean original idea, we searched for the coherence as the philosophy of the service age in the Korean representative ideology. The basic structure and operation model of service philosophy are presented, and the service philosophy of major korean ideology is derived. The philosophy of service can be presented by the structure of service and the operation of service. The essential characteristics of the service are relationship, interactivity, horizontality, and harmony, and the service structure that reflects this is the coexistence of products and services. Based on the discussion on the structure and operation of the service philosophy, the service philosophy synthesis of Korean representative ideology is presented. From the Silla era to the Koryo dynasty, the essence of Korean Buddhism thought is in line with the service philosophy, and it was found that Toegye and Yulgok to Dasan's thoughts are also consistent with service philosophy. In the future, we need further studies to refine the structure and operational principles of the service philosophy and to develop it into a big idea. In addition, it is necessary to follow up the service philosophy of Oriental representative ideology centering on Chinese and Indian philosophy. Ultimately, it is necessary to establish a service philosophy as the main philosophical thought and to establish a service philosophy as a desirable future economic and social philosophy.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.5
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• pp.405-418
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• 2007

Mesenchymal stem cells(MSCs) have been though to be multipotent cells that can replicate that have the potential to differentiate into lineages of mesenchymal tissue including the bone, cartilage, fat, tendon, muscle, and marrow stroma. Especially, scaffolds to support cell-based tissue engineering are critical determinants of clinical efforts to regenerate and repair the body. Selection of a matrix carrier imvolves consideration of the matrix's role as a scaffold for physical support and host tissue integration as well as its ability to support of synergize the osteoinductive program of the implanted mesenchymal stem cell. The aim of this study is to evaluate the effect of autobone and Bio-$Oss^{(R)}$ to adherent mesenchymal stem cells as scaffolds on sinus augmentation with fibrin glue mixture in a rabbit model. 16 New Zealand White rabbits were divided randomly into 4 groups based on their time of sacrifice(1, 2, 4 and 8 weeks). First, mesenchymal stem cells were isolated from iliac crest marrow of rabbits and expanded in vitro. Cell culture was performed in accordance with the technique described by Tsutsumi et al. In the present study, the animals were sacrificed at 1, 2, 4 and 8 weeks after transplantation, and the bone formation ability of each sides was evaluated clinically, radiologically, histologically and histomorphologically. According to the histological observations, autobone scaffolds group showed integrated graft bone with host bone from sinus wall. At 2 and 4 weeks, it showed active newly formed bone and neovascularization. At 8 weeks, lamellae bone was observed in sinus graft material area. Radiologically, autobone with stem cell showed more radiopaque than Bio-$Oss^{(R)}$ scaffolds group. there were significant differences in bone volume between 4 and 8 weeks(p<0.05).

• Journal of dental hygiene science
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• v.2 no.2
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• pp.63-67
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• 2002

The purpose of this study was to develop more effective dental health education program and to reduce the occurrence of dental diseases among industrial men-workers in Korea. The questionaire and dental examination were given to 782 industrial men-workers who visited Asan Medical Center for the purpose of health examinations in 2000. The obtained results were as follows; 1. According to the results of logistic regression analysis, both ages (especially under 30's: P=0.027) and monthly incomes (especially under 1,000,000 won: P=0.000) show negative relationships with the occurrence of dental caries. 2. As the results of logistic regression analysis, ages shows positive relationship and monthly incomes shows negative relationship (only under 1,000,000 won: P=0.059) with the occurrence of missing teeth. 3. According to the results of logistic regression analysis of periodontal disease, the model shows no significance (P=0.117). 4. As the results of logistic regression analysis, both monthly incomes and ages show positive relationships with the occurrence of abrasion.

• Journal of Digital Convergence
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• v.13 no.1
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• pp.297-304
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• 2015

Recently, the demand for a PRT(Personal Rapid Transit) system based on autonomous navigation is increasing. Accordingly, the applicability investigations of the PRT system on rail tracks or roadways have been widely studied. In the case of unmanned vehicle operations without physical guideways on roadways, to monitor the position of the vehicle in real time is very important for stable, robust and reliable guidance of an autonomous vehicle. The Global Positioning System (GPS) has been commercially used for vehicle positioning. However, it cannot be applied in environments as tunnels or interiors of buildings. The PRT navigation system based on magnetic markers reference sensing that can overcome these environmental restrictions and the vehicle dynamics model for its H/W configuration are presented in this study. In addition, the design of a control S/W dedicated for unmanned operation of a PRT vehicle and its prototype implementation for experimental validation on a pilot network were successfully achieved.

• Journal of Digital Convergence
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• v.11 no.1
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• pp.99-106
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• 2013

Personal information protection has become one of the most impending business issues because leakage of personal information can cause tremendous financial losses and image degradation. Consequently, personal information protection initiatives have been recognized widely in business. To invigorate personal information protection investments, performance measurement method such as cost benefits analysis or qualitative analyses are needed, which have not been studied enough in the previous studies. This study proposes a performance measurement model which can include quantitative and qualitative analyses in the context of personal information protection investments. A comparative analysis has been performed on security investment and IT investment performance measurements, which leads to choose the WiBe method (developed by the German Interior Ministry), considering the privacy characteristics and the method's applicability. In particular, the quantitative effect measured how proactive threat assessment based on the way according to the nature of the businesses and organizations of privacy and possible investment decisions. This study proposes the 16 performance indicators, which turn out to be meaningful in terms of their materiality and feasibility by conducting focus group interviews of 25 experts on personal information protection.

• Journal of Digital Convergence
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• v.11 no.10
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• pp.59-69
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• 2013

20s country employment rate to 57% in the last four years, is staying low. College graduates in the 25-29 year old crowd real unemployment rate is over 20% youth unemployment, the analysis problem is serious enough. Accordingly, activation of Cooperation, which addresses the issues of these countries now being recognized as the primary means, and in the future, government policy and national indicators to be given more attention and support seems clear. Government from 2012 'Cooperation Development Project leading universities' (LINC: Leaders in INdustry-university Cooperation) by promoting companies that require manpower, actual research and development and technology transfer to enable the University - Industry - between research institutions based on organic correlated with local universities and industrial growth model for the creation of a variety of leading industry cooperation. has to diffuse. This background, the aim of this study at the University of excavation site close-type talent. Fostering curriculum development are essential to the field on the form will close. In this study, major department (Department) conducted by major research based on the results of the curriculum needs to spread the field for Cooperation closely analyze the curriculum and Annual type, domain-specific promotion measures proposed.