• Journal of Distribution Science
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• v.14 no.9
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• pp.85-94
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• 2016

Purpose - Recently, Mobile technologies and devices including smart phones and tablets have increased the possibility of communicating with other people and sharing personal information without time and space restriction. In order to realize the market potential related to mobile technologies, a large number of internet services have been incorporated into mobile platforms. Especially, The number of MIM(Mobile Instant Messenger) users has been increasing dramatically and services using MIM platform also have diversified. In spite of drastic growth in markets related to MIM, there is little empirical research on MIM and users' behaviors. This study designed to examine the structural relationships among belongingness, loneliness, self-disclosure intention, system quality, and self-disclosure behavior in context of MIM. Research design, data, and methodology - Three hypotheses were about the relationship among belongingness, loneliness and self-disclosure intention. The other two hypotheses were about the moderating effect of system quality in the causal relationship between self-disclosure intention and self-disclosure behavior. The data was analyzed by structural equation modeling. Research data were obtained from 330 undergraduate students who were KakaoTalk users and total 314 valid questionnaires were used in the final analysis. Results - The results from this study are as follow. First, the belongingness and the loneliness had a significant impact on self-disclosure intention in MIM. Second, the self-disclosure intention in MIM also had a positive impact on the self-disclosure behavior. Lastly, there is a moderating effect of the system quality in the relationship between the self-disclosure intention and self-disclosure behavior in MIM. Specifically, the higher system quality level was perceived, the positive effect of the self-disclosure intention in MIM on the self-disclosure behavior was greater. Conclusions - Based on the results from this study, academic and practical implications can be drawn. First, the study extends the scope of research about SNS through focusing on MIM to be classified by closed type SNS and identifies the relationship between emotion, behavioral intention and behaviors in MIM. Second, this study provides strategic guidelines to increase the efficiency for promotion activity. Limitations for the study also should be discussed.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.1
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• pp.7-15
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• 2014

Image retrieval has become a huge part of computer vision and data mining. Although commercial image retrieval systems such as Google show great performances, the improvement on the performances are constantly on demand because of the rapid growth of data on web space. To satisfy the demand, many re-ranking methods, which enhance the performances by reordering retrieved results with independent algorithms, has been proposed. Conventional re-ranking algorithms are based on the assumption that visual patterns are not used on initial image retrieval stage. However, image search engines in present have begun to use the visual and the assumption is required to be reconsidered. Also, though it is possible to suspect that integration of multiple retrieval systems can improve the overall performance, the research on the topic has not been done sufficiently. In this paper, we made the condition that other manner than cooperation cannot improve the ranking result. We evaluate the algorithm on toy model and show that propose module can improve the retrieval results.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.3
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• pp.27-36
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• 2004

Detection and recognition of human faces in images can be considered as an important aspect for applications that involve interaction between human and computer. In this paper, we propose a face recognition method using eigenfaces and fuzzy neural networks. The Principal Components Analysis (PCA) is one of the most successful technique that have been used to recognize faces in images. In this technique the eigenvectors (eigenfaces) and eigenvalues of an image is extracted from a covariance matrix which is constructed form image database. Face recognition is Performed by projecting an unknown image into the subspace spanned by the eigenfaces and by comparing its position in the face space with the positions of known indivisuals. Based on this technique, we propose a new algorithm for face recognition consisting of 5 steps including preprocessing, eigenfaces generation, design of fuzzy membership function, training of neural network, and recognition. First, each face image in the face database is preprocessed and eigenfaces are created. Fuzzy membership degrees are assigned to 135 eigenface weights, and these membership degrees are then inputted to a neural network to be trained. After training, the output value of the neural network is intupreted as the degree of face closeness to each face in the training database.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.9
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• pp.15-22
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• 2000

The effects of carrier transport and input power on the extinction ratio was theoretically analyzed in a 1.55${\mu}m$ InGaAsP/InGaAsP multiple-quantum-well(MQW) electroabsorption(EA) modulator. Poisson's equation, current continuity equations for electrons and holes, and optical field distribution were self-consistently solved by considering electric field dependent absorption coefficients. The field screening effect due to the carrier accumulation in heterointerface and the space-charge region occurred more seriously at the input side of modulator as input optical intensity increased. It was revealed that extinction ratio could be steeply degraded for modulator with the length of 200${\mu}m$ when an input power exceeds 10mW. A degradation of extinction ratio due to the field screening effect would be more significantly at high-performance devices such as a 1.55${\mu}m$DFB-LD/EA-modulator integrated source where optical coupling efficiency is almost complete or a very high-speed modulator with its length as short as a few tens ${\mu}m$.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.5 s.305
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• pp.85-94
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• 2005

Display characterization, deriving the relationship between digital input values and the corresponding CIEXYZ tri-stimulus values, is important to reproduce the accurate color in color management system. The relationship can be estimated from the nine channel TRCs(tone response curves) and the result of this characterization method is better than that of using three channel TRCs. However, the inverse display characterization using nine channel TRCs cannot be directly inverted because the CIEXYZ values corresponding to each of RGB values are inseparable. Accordingly, inverse display characterization is usually implemented by the 3D-LUT (look-up table) method. Although the result of 3B-LUT is accurate, creating the 3D-LUT requires a lot of memory space and considerable amount of measurements. Therefore the inverse characterization method is proposed based on the modeling of channel-dependent values and nine channel inverse process based on the GOG(gain, offset gamma) model. The proposed method enhances the accuracy of display characterization and reduces the complexity and the number of measurements data required for accuracy in 3-D LUT.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.1
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• pp.19-30
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• 2012

For digital data compression, the quantization is the main part of the lossy source coding. In order to improve the performance of quantization, the vector quantizer(VQ) can be employed. The encoding complexity, however, exponentially increases as the vector dimension or bit rate gets large. Much research has been conducted to alleviate such problems of VQ. Especially for high bit rates, a constrained VQ, which is called the sample-adaptive product quantizer(SAPQ), has been proposed for reducing the hugh encoding complexity of regular VQs. SAPQ has very similar structure as to the product VQ(PQ). However, the quantizer performance can be better than the PQ case. Further, the encoding complexity and the memory requirement for the codebooks are lower than the regular full-search VQ case. Among SAPQs, 1-SAPQ has a simple quantizer structure, where each product codebook is symmetric with respect to the diagonal line in the underlying vector space. It is known that 1-SAPQ shows a good performance for i.i.d. sources. In this paper, a study on designing 1-SAPQ for the first-order Markov process. For an efficient design of 1-SAPQ, an algorithm for the initial codebook is proposed, and through the numerical analysis it is shown that 1-SAPQ shows better quantizer distortion than the VQ case, of which encoding complexity is similar to that of 1-SAPQ, and shows distortions, which are close to that of the DPCM(differential pulse coded modulation) scheme with the Lloyd-Max quantizer.

• Journal of the Economic Geographical Society of Korea
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• v.6 no.2
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• pp.443-470
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• 2003

This study is to consider economic, political, socio-cultural and environmental characteristics of the new urbanization process and its spatial structures and urban policy of Seoul in the 1990s. Some experimental findings which have been identified throughout this study can be summarized as follows. First of all, Seoul, the largest city in S.Korea has experienced a restructuring process of economy, which has been promoted by the development of producer services as well as knowledge- based or high tech industries. Secondly, the autonomy of Seoul has increased after the introduction of local self-government, with relatively higher self-management of local finance than other cities, strengthening the tendency of enterpreneurialism, empowering civil movements, and increasing the political participation of women. Thirdly, in the socio-cultural aspect, the material wants to gain a certain identity through consumption, using urban environments culturally, varying consuming attitudes and ways of leisure times in relation with the rapid development of transportation and information communication. Fourthly, in the environmental aspect, Seoul has tried to introduce the concept of sustainable development in terms of increasing wants on the quality of life, and to develop a pro-environmental eco-city with environmental rehabilitation, constructing green space and eco-park. Finally, in the spatial dimension, Seoul has shown a structuration of multi-centers, with highly spectacular urban landscapes and seemingly authentic urban planning. These results make us confirm that Seoul has been in the process of new urbanization which can be distinguished from the previous one.

• Journal of the Economic Geographical Society of Korea
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• v.16 no.4
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• pp.567-584
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• 2013

This study aims to explore an evolutionary path of the IT service industry in Fairfax County using the Cluster Adaptive Cycle model in economic geography. The analysis is based on detailed historical and industrial information obtained through a variety of data sources including local archival materials, economic census, and interviews. This study also performs a shift-share analysis during the period of 1990 to 2011. Using the adaptive cycle model, the local IT service industry is indicated by a trajectory of constant cluster mutation. The evolution of the local IT service industry has been closely related to federal government policy due to the regional specificity of the National Capital Region and the proximity of the Department of Defense. Although the economic downturn of the late 2000s, the local IT service industry has been notable resilience and adapted to a changing market and technological environment. This constant mutation of the local industry is resulted from not only high resilience which is based on the large government procurement market, the reinforcement of adaptive capacity of the local firms and the network of economic agents such as firm and supporting institutions, but also high flexibility of the knowledge-based service industry to a changing business environment.

• Journal of Korean Society of Forest Science
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• v.94 no.6
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• pp.462-467
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• 2005

This study aims to classify the biotope types and evaluate its functions for acquiring the basic information which can support the landscape ecological management of the urban forest in the case of the three parks in Daegu metropolitan city and then to analyze vegetation landscape patterns. The biotope classification was mostly divided into 5 to 6 biotope type groups in the high units and 15 to 20 biotope types belong to them and then could know that the more big the park size, the more diverse and large the biotope types and its average area. The biotope grade over the three parks was dominating low rank grade (1 to 3 grade) 72.7% that forest organism is inadequate as live, and high grade (7 to 9 grade) did not appear entirely. Most in Biotope function estimation were appeared less than the middle rank grade and biotope area is bigger, those grade rises and temperature could know that is fallen. Vegetation landscape patterns was very simple because only two kinds of Robinia pseudo-acacia and Quercus acutissima is appeared as the dominated landscape elements in all of the three parks. And also because average area of those elements is generally 1ha or so, there was much problems in consecutiveness of functional role as forest ecosystem component. Conclusively, Ecological landscape management need to improve Biotope diversity and functionality, and it secures ecological minimal area and space linkage.

• Journal of the Korean Geographical Society
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• v.48 no.2
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• pp.259-271
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• 2013

This paper addresses the efficient facility placements to adopt a super WiFi network, taking significant considerations as the next generation 'information highway'. Since the super WiFi has a wider geographic coverage by utilizing the white spaces of TV broadcasting which are empty and available frequencies for the wireless communications, it would play an important role in releasing digital divide of the internet access for low populated or mountainous areas. The purpose of this paper is to explore systematic and efficient spatial plans for the super WiFi. For doing this, we applied optimal location covering models to Gurye-gun, Jeonlanamdo. From the application, we presented optimal locations for super WiFi facilities and significant analytical results, such as the tradeoff between the number of facilities and coverage and marginal coverage for establishing super WiFi network. The results of this research would be usefully utilized for decision makers who wish to adopt a super WiFi, to extend wireless networks in a city or build a regional infrastructure of wireless facilities.