• The Journal of Information Systems
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• v.27 no.1
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• pp.43-65
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• 2018

Purpose The emergence of mobile applications has simplified our life in various ways. Regarding tourism activities, mobile applications are already efficient in providing personalized tourism related information and are very much effective in booking hotels, flights, etc. However, there are very few studies on classifying the actual service requirements and improving the customer satisfaction in mobile tourism applications. The purpose of this study is to implement a practical mobile tourism application. To serve the purpose, we classify and categorize the service requirement of mobile tourism applications in Korea. We employed Kano model and analytic hierarchy process (AHP). Specifically, we conducted a focus group study to find out the service requirements in mobile tourism applications. Design/methodology/approach The data for this study were collected from Koreans and Foreigners who has the experience using mobile tourism applications. Participants needed to be familiar with mobile tourism applications because such users may be more aware of the mobile tourism applications services. We analyzed 147 valid data using Kano model and conducted AHP analysis on five experts in the field of tourism using Expert Choice software. Findings In this paper, we identified the 17 service quality requirements in the mobile tourism applications. The results reveal that the service requirement such as Geo-location map, Multilingual option, Compatibility with different operating systems were unavoidable service, absent of such requirements leads to the dissatisfaction. Based on the results of the integrated application of both Kano model and AHP analysis, this study provide specific implications for improving the service quality of the mobile tourism applications in Korea.

• Korean Journal of Community Nutrition
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• v.14 no.1
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• pp.1-11
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• 2009

The aims of this study were to assess the quality of breakfast intake and to examine the relation of breakfast intake to the quality of daily diet in Korean school-aged children. The one day 24-hour recall data from the 2001 National Health and Nutrition Survey were analyzed. The sample of this study consisted of 1,600 children aged 7 to 18 years attending elementary, middle, or high schools. By calorie level of breakfast intake, the children were grouped into Breakfast Skippers (0 kcal; n = 268, 17%), Low Calorie Breakfast Eaters (0 kcal < and < 10% of Estimated Energy Requirement (EER); n = 190, 12%), Moderate Calorie Breakfast Eaters (10% ${\leq}$ and < 25% of EER; n = 861, 54%), or Sufficient Calorie Breakfast Eaters (${\geq}$ 25% of EER; n = 281, 17%). General characteristics including weight status and nutritional quality of breakfast and daily diet were compared among the four groups. The average daily calorie intake of Breakfast Skippers, Low, Moderate, and Sufficient Breakfast Eaters were 1,771 kcal, 1,719 kcal, 1,902 kcal, and 2,349 kcal, respectively; they were 86.3%, 85.9%, 98.0%, and 124.9% of EER, respectively. The percentages of students consuming daily diet with protein, vitamin A, $B_1$, $B_2$, niacin, vitamin C, calcium, phosphorus, or iron less than Estimated Average Requirement decreased in the breakfast groups with the higher calorie level of breakfast intake. The Dietary Variety Score of daily diet significantly increased by increasing the calorie level of breakfast intake. The results indicated the quality of daily diet was positively related to the level of calorie intake from breakfast.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1A
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• pp.76-83
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• 2009

In this paper, we provide opportunistic scheduling schemes for elastic services in OFDMA systems with fairness constraints for each user. We adopt the network utility maximization framework in which a utility function is defined for each user to represent its level of satisfaction to the service. Since we consider elastic services whose degree of satisfaction depends on its average data rate, we define the utility function of each user as a function of its average data rate. In addition, for fair resource allocation among users, we define fairness requirements of each user by using utility functions. We first formulate an optimization problem for each fairness requirement that aim at maximizing network utility, which is defined as the sum of utilities of users. We then develop an opportunistic scheduling scheme for each fairness requirement by solving the problem using a dual approach and a stochastic sub-gradient algorithm.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.1
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• pp.46-56
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• 2008

Double Patching is a multicasting technique for a VoD system which has been proposed to provide a true VoD service by making clients share a long patching stream as well as a regular stream For subsequent short patching streams, the technique always makes the long patching stream have extra data that will be played back during a double period of a patching window. In this paper, we propose a technique, using the start time of the latest short patching stream, optimizes Double Patching by deleting the useless data included in the long patching stream when the patching window of the long patching stream closes. The mean requirement for the server's bandwidth to provide the true VoD service is used as a performance metric, and the effect of the request inter-arrival time, the size of the client's local buffer and the video length on the mean bandwidth requirement is evaluated. Performance evaluation result shows that the proposed technique optimizes Double Patching in all cases.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1325-1344
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• 2019

Recently, to satisfy mobile users' increasing data transmission requirement, energy efficiency (EE) resource allocation in distributed antenna systems (DASs) has become a hot topic. In this paper, we aim to maximize EE in DASs subject to constraints of the minimum data rate requirement and the maximum transmission power of distributed antenna units (DAUs) with different density distributions. Virtual cell is defined as DAUs selected by the same user equipment (UE) and the size of virtual cells is dependent on the number of subcarriers and the transmission power. Specifically, the selection rule of DAUs is depended on different scenarios. We develop two scenarios based on the density of DAUs, namely, the sparse scenario and the dense scenario. In the sparse scenario, each DAU can only be selected by one UE to avoid co-channel interference. In order to make the original non-convex optimization problem tractable, we transform it into an equivalent fractional programming and solve by the following two sub-problems: optimal subcarrier allocation to find suitable DAUs; optimal power allocation for each subcarrier. Moreover, in the dense scenario, we consider UEs could access the same channel and generate co-channel interference. The optimization problem could be transformed into a convex form based on interference upper bound and fractional programming. In addition, an energy-efficient DAU selection scheme based on the large scale fading is developed to maximize EE. Finally, simulation results demonstrate the effectiveness of the proposed algorithm for both sparse and dense scenarios.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.2
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• pp.45-56
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• 2013

The precise identification of vehicle positions, known as the vehicle localization problem, is an important requirement for building intelligent vehicle ad-hoc networks (VANETs). To solve this problem, two categories of solutions are proposed: stand-alone and data fusion approaches. Compared to stand-alone approaches, which use single information including the global positioning system (GPS) and sensor-based navigation systems with differential corrections, data fusion approaches analyze the position information of several vehicles from GPS and sensor-based navigation systems, etc. Therefore, data fusion approaches show high accuracy. With the position information on a set of vehicles in the preprocessing stage, data fusion approaches is used to estimate the precise vehicular location in the local map building stage. This paper proposes an efficient local map building scheme, which increases the accuracy of the estimated vehicle positions via V2V communications. Even under the low ratio of vehicles with communication modules on the road, the proposed local map building scheme showed high accuracy when estimating the vehicle positions. From the experimental results based on the parameters of the practical vehicular environments, the accuracy of the proposed localization system approached the single lane-level.

• Journal of the Korea Society of Computer and Information
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• v.9 no.3
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• pp.1-6
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• 2004

there needs a new Geographic information system development Technology of the abstraction, encapsulation, modulation and hierarchy using Graphic representation of object modeling Technique. The method is based on composite object of Graphic data with the hierarchy concepts and abstraction of Graphic information in order to improve data abstraction of the graphic data file and described concept of multiple inheritance and classification that supports a wide variety of graphic class such as mesh unit, layer. segment and so on. in simple case of software development using SPICE model and object modeling techniques. this thesis suggested object representation of Graphic data which can reduce software development life cycle and the cost of software maintenance.

• Korean Journal of Remote Sensing
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• v.27 no.6
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• pp.729-741
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• 2011

Wind speeds have long been estimated from C-band VV-polarized SAR data by using the CMOD algorithms such as CMOD4, CMOD5, and CMOD_IFR2. Some SAR data with HH-polarization without any observations in VV-polarization mode should be converted to VV-polarized value in order to use the previous algorithms based on VV-polarized observation. To satisfy the necessity of polarization ratio (PR) for the conversion, we retrieved the conversion parameter from full-polarized SIR-C SAR image off the east coast of Korea. The polarization ratio for SIR-C SAR data was estimated to 0.47. To assess the accuracy of the polarization ratio coefficient, pseudo VV-polarized normalized radar cross section (NRCS) values were calculated and compared with the original VV-polarized ones. As a result, the estimated psudo values showed a good agreement with the original VV-polarized data with an root mean square error by 0.99 dB. We applied the psudo NRCS to the estimation of wind speeds based on the CMOD wind models. Comparison of the retrieved wind field with the ECMWF and NCEP/NCAR reanalysis wind data showed relatively small rms errors of 1.88 and 1.91 m/s, respectively. SIR-C HH-polarized SAR wind retrievals met the requirement of the scatterometer winds in overall. However, the polarization ratio coefficient revealed dependence on NRCS value, wind speed, and incident angle.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.7
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• pp.1626-1633
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• 2010

In this paper, we implemented medicinal plant information system based on user requirement using Ajax technique which can retrieve data from the server asynchronously in the background without refresh webpage and jQuery which is a lightweight cross-browser javascript library. Also, we presented the source code handling the server response data used in the system and compared the features by the type of response data. This system shows the improvement of user interaction and response rates because of a simple response data from the server, client-side data processing and change of web page by manipulating the DOM tree and provides ease of use and convenient data access.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.4
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• pp.522-531
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• 2010

Appropriate networks are required for the processing of various kinds of data generated on shipboard. The international standards, NMEA 2000 and IEC 61161-4, meet this requirement. NMEA 2000 is good for the processing of real time data, and IEC 61162-4 is better for the integrated management of such data. Therefore, NMEA 2000 data should be conversed into IEC 61162-4 format for the integrated management. This paper presents files and algorithm for the format conversion, and also describes their implementation.