• Journal of Korean Society for Geospatial Information Science
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• v.17 no.1
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• pp.43-52
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• 2009

LIDAR data, as the source of the 3D information of buildings, are used many modeling fields such as three-dimensional city models in urban planning and the visibility analysis of buildings. This study suggests a methodology, that is characterized by combining image-based and point-based process, for minimizing the user's intervention and automatically extracting building boundary only using the LIDAR data. Image processing methodology is firstly used to separate building and non-building regions from LIDAR data. Moreover, building regions are then classified main roof into remaining parts by the statistical analysis of height values, and the remaining parts are processed separately. Through the experimental results of study areas which exist many types of buildings, for example, apartment-type, stair-type, complex-type, etc. Approximately 90% building boundaries are automatically extracted by the proposed methodology.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.3876-3895
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• 2014

Recently, Heterogeneous Network (HetNet) with Coordinated Multi-Point (CoMP) scheme is introduced into Long Term Evolution-Advanced (LTE-A) systems to improve digital services for User Equipments (UEs), especially for cell-edge UEs. However, Radio Resource Management (RRM), including Resource Block (RB) scheduling and Power Allocation (PA), in this scenario becomes challenging, due to the intercell cooperation. In this paper, we investigate the RRM problem for downlink transmission of HetNet system with Joint Processing (JP) CoMP (both joint transmission and dynamic cell selection schemes), aiming at maximizing weighted sum data rate under the constraints of both transmission power and backhaul capacity. First, joint RB scheduling and PA problem is formulated as a constrained Mixed Integer Programming (MIP) which is NP-hard. To simplify the formulation problem, we decompose it into two problems of RB scheduling and PA. For RB scheduling, we propose an algorithm with less computational complexity to achieve a suboptimal solution. Then, according to the obtained scheduling results, we present an iterative Karush-Kuhn-Tucker (KKT) method to solve the PA problem. Extensive simulations are conducted to verify the effectiveness and efficiency of the proposed algorithms. Two kinds of JP CoMP schemes are compared with a non-CoMP greedy scheme (max capacity scheme). Simulation results prove that the CoMP schemes with the proposed RRM algorithms dramatically enhance data rate of cell-edge UEs, thereby improving UEs' fairness of data rate. Also, it is shown that the proposed PA algorithms can decrease power consumption of transmission antennas without loss of transmission performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.5
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• pp.2484-2498
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• 2017

Various types of social media make the people share their personal experience in different ways. In some social networking sites. Some users post their reviews, some users can support these reviews with comments, and some users just rate the reviews as kind of support or not. Unfortunately, there is rare explicit negative comments towards other reviews. This means if there is a link between two users, it must be positive link. Apparently, the negative link is invisible in these social network. Or in other word, the negative links are redundant to positive links. In this work, we first discuss the feature extraction from social media data and propose new method to compute the distance between each pair of comments or reviews on social media. Then we investigate whether we can predict negative links via regression analysis when only positive links are manifested from social media data. In particular, we provide a principled way to mathematically incorporate multi-facet data in a novel framework, Constructing Negative Links, CsNL to predict negative links for discovering the hidden information. Additionally, we investigate the ways of solution to general negative link predication problems with CsNL and its extension. Experiments are performed on real-world data and results show that negative links is predictable with multi-facet of social media data by the proposed framework CsNL. Essentially, high prediction accuracy suggests that negative links are redundant to positive links. Further experiments are performed to evaluate coefficients on different kernels. The results show that user generated content dominates the prediction performance of CsNL.

• Journal of Digital Convergence
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• v.14 no.4
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• pp.201-208
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• 2016

Recently, non-standard techniques of web like Active-X caused not only user inconvenience but also barriers to the business of Internet. The government recognized that the serious environmental situation of using Internet is needed to be improved. Especially, HTML5 convergence technology is meant to be a specific platform over the devices, users, and systems. It also means web standards to support more creative business service model and emerging market. In this paper, we performed a survey on Web standards compliance and web development professional level of domestic web developers. In addition, we present the basic direction of government policy of software and software-positive human resources policy, that is based on the analysis of the survey results. Our study will be able to contribute to construct policies to support digital convergence industry and to strengthen technical assistance and expertise to build training programs for the spread of global Web standards (HTML5).

• Journal of Science and Technology Studies
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• v.6 no.2 s.12
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• pp.103-129
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• 2006

In spite of decreased attention to digital divide, it has been pointed out as one of the main obstacles to realization of information society. At the outset, two conflicting explanations, optimism and pessimism, have directed their attention to objective basis of digital divide in common. They, however, have been neglected the fact that accessibilities can be varied not only by objective conditions but by subjective conditions such as individual recognition of necessity and willingness. Subsequent choices can be a crucial factor to determine whether to or not to access. In USA, over 50% of potential users determined not to access to the internet by their own will and choices. By the user survey on internet, 'do not feel the necessity' ranked the first reason not to use the internet in South Korea. The respondents who chose 'no time to use' tend to decrease but kept holding their shares, too. The relative importance of 'not to access' by individual choice have been increased. Whether the non-users of ICTs by choice is in or beyond the scope of digital divide, it evidently shows the necessity and importance of directing our attention to it on the way to information society.

• Journal of Communications and Networks
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• v.14 no.6
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• pp.662-671
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• 2012

Plug-in hybrid electric vehicles (PHEVs) will be widely used in future transportation systems to reduce oil fuel consumption. Therefore, the electrical energy demand will be increased due to the charging of a large number of vehicles. Without intelligent control strategies, the charging process can easily overload the electricity grid at peak hours. In this paper, we consider a smart charging and discharging process for multiple PHEVs in a building's garage to optimize the energy consumption profile of the building. We formulate a centralized optimization problem in which the building controller or planner aims to minimize the square Euclidean distance between the instantaneous energy demand and the average demand of the building by controlling the charging and discharging schedules of PHEVs (or 'users'). The PHEVs' batteries will be charged during low-demand periods and discharged during high-demand periods in order to reduce the peak load of the building. In a decentralized system, we design an energy cost-sharing model and apply a non-cooperative approach to formulate an energy charging and discharging scheduling game, in which the players are the users, their strategies are the battery charging and discharging schedules, and the utility function of each user is defined as the negative total energy payment to the building. Based on the game theory setup, we also propose a distributed algorithm in which each PHEV independently selects its best strategy to maximize the utility function. The PHEVs update the building planner with their energy charging and discharging schedules. We also show that the PHEV owners will have an incentive to participate in the energy charging and discharging game. Simulation results verify that the proposed distributed algorithm will minimize the peak load and the total energy cost simultaneously.

• Korean Journal of Optics and Photonics
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• v.13 no.6
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• pp.493-500
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• 2002

Fingerprint recognition is concerned with fingerprint acquisition and matching. Our research was focused on a fingerprint matching method using an inkless fingerprint input sensor at the fingerprint acquisition step. Since an inkless fingerprint sensor produces a digital-image-processed fingerprint image, we did not consider noise that can happen while acquiring the fingerprint. And making the user attempt fingerprint input as random, we considered image distortion that translation and rotation are included as complex. NJTC algorithm is used for fingerprint identification and verification. The method to find the center of the fingerprint is added in the NJTC algorithm to supplement discrimination of fingerprint recognition. From this center point, we decided the optimum cropping size for effective matching with pixels and demonstrated that the proposed method has high discrimination and high efficiency.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.8 no.3
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• pp.187-196
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• 2014

This paper suggests linearity enhancement algorithm to Ensure safety of Mobile Walker on Slope. Mobile Walker happens to get off track due to external forces from Walker's weight and the degree of the slope while slope driving. In order to compensate this, this research used the controller that estimates the external forces according to the slope of road surface and adjusts it to the motor output. Also, through comparisons between targeted rotational angular velocity which the user inputs and its velocity of the robot, algorithm was applied which applies a weight to each shaft. As a result of applying the proposed correction controller, it diverges in case of non-compensation experiments that deviates when moving, but it case of applying the ramp calibration algorithm, the deviation distance at max was within 10cm that it keeps safe driving, and change rate of deviation distance was also stabilized after 1m where no more changes occurred.

• Journal of Digital Convergence
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• v.14 no.1
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• pp.379-386
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• 2016

This study explored Korean college students' smartphone game behavior for the pastime. Smartphone games have weakness that is not appropriate for playing the game because of small screen and non-sophisticated interface for operation. To defeat the disadvantage, the games employed minimalism like conciseness or simplicity. The study explored how conciseness influences perceived ease of use, perceived enjoyment, flow, and intent to use the game through PLS path modeling. We found that every hypothesis except a path, perceived ease of use to flow, proved significant. This result means that smartphone game design should consider the interface of users' convenience and user experience practically. Finally, based on the findings, suggestions for future studies were discussed.

• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.43-52
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• 2006

LRecently, with increasing interest in ubiquitous computing, knowledge discovery method is needed with consideration of the efficiency and the effectiveness of wide range and various forms of data. Spatial Characterization which extends former characterization method with consideration of spatial and non-spatial property enables to find various form of knowledge in spatial region. The previous spatial characterization methods have the problems as follows. Firstly, former study shows the problem that the result of searched knowledge is unable to perform the multiple spatial analysis. Secondly, it is unable to secure the useful knowledge search since it searches the limited spatial region which is allocated by the user. Thus, this study suggests spatial characterization which applies to density based clustering.