• Journal of the Korea Society of Computer and Information
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• v.16 no.9
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• pp.87-95
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• 2011

Recently, as smartphones have rapidly come into wide use and various social networking services have grown, people perform a variety of interactions through the virtual and real world based on them. Usually, such services focus on easy formation of social links among users, supporting the exchange of simple messages among users on the networks. Twitter, one of such services used worldwide, supports short message service named Tweet and has over 200 million members signed up. n this paper, we propose techniques for supporting real-time group messaging based on the social network of Twitter and describe a smartphone group messaging system developed with the techniques. The system automatically forms a group that include a Twitter user and the followers of the user, supporting real-time group messaging among the group members. The developed system is composed of an XMPP protocol-based messaging server and smartphone client applications which perform real-time messaging based on the social network of Twitter. Twitter users can easily use the system utilizing Tweet messages, exchanging real-time messages with their followers within the groups instantly established on the XMPP server.

• Safety and Health at Work
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• v.10 no.4
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• pp.452-460
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• 2019

Background: Monitoring and control of PM_2.5 are being recognized as key to address health issues attributed to PM_2.5. Availability of low-cost PM_2.5 sensors made it possible to introduce a number of portable PM_2.5 monitors based on light scattering to the consumer market at an affordable price. Accuracy of light scatteringe-based PM_2.5 monitors significantly depends on the method of calibration. Static calibration curve is used as the most popular calibration method for low-cost PM_2.5 sensors particularly because of ease of application. Drawback in this approach is, however, the lack of accuracy. Methods: This study discussed the calibration of a low-cost PM_2.5-monitoring device (PMD) to improve the accuracy and reliability for practical use. The proposed method is based on construction of the PM_2.5 sensor network using Message Queuing Telemetry Transport (MQTT) protocol and web query of reference measurement data available at government-authorized PM monitoring station (GAMS) in the republic of Korea. Four machine learning (ML) algorithms such as support vector machine, k-nearest neighbors, random forest, and extreme gradient boosting were used as regression models to calibrate the PMD measurements of PM_2.5. Performance of each ML algorithm was evaluated using stratified K-fold cross-validation, and a linear regression model was used as a reference. Results: Based on the performance of ML algorithms used, regression of the output of the PMD to PM_2.5 concentrations data available from the GAMS through web query was effective. The extreme gradient boosting algorithm showed the best performance with a mean coefficient of determination (R²) of 0.78 and standard error of 5.0 ㎍/㎥, corresponding to 8% increase in R² and 12% decrease in root mean square error in comparison with the linear regression model. Minimum 100 hours of calibration period was found required to calibrate the PMD to its full capacity. Calibration method proposed poses a limitation on the location of the PMD being in the vicinity of the GAMS. As the number of the PMD participating in the sensor network increases, however, calibrated PMDs can be used as reference devices to nearby PMDs that require calibration, forming a calibration chain through MQTT protocol. Conclusions: Calibration of a low-cost PMD, which is based on construction of PM_2.5 sensor network using MQTT protocol and web query of reference measurement data available at a GAMS, significantly improves the accuracy and reliability of a PMD, thereby making practical use of the low-cost PMD possible.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.91-98
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• 2004

This study focuses on the development of dynamic assignment for evaluation and application for dynamic route guidance strategy. Travelers are classified according to information contents which they received pre/on trip. The first group have no traffic information, so they travel with fixed route. The second group have real-time shortest path and travel according to it. The last group have car navigation system or individual method(cellular phone, PDA-two way communication available) for traffic information on trip. And then they are assigned in accordance with the proposed multiclass dynamic assignment model. At this time the last group is gotten under control with DFS(decentralized feedback strategy). In use of this Process we expect that various traffic information strategy can be tested and also be the key factor for success of ITS, location of VMS(variable message sign), cycle of information, area of traffic information, etc).

• Journal of Advanced Navigation Technology
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• v.14 no.5
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• pp.684-690
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• 2010

Recently, the NG(Next Generation) system is studied for supporting convergence of various services and multi mode of single terminal. And a demand of user for taking the various services is getting increased, for supporting these services, many systems being able to transmit a large message have been appeared. In the NG system, it has to be supporting the CDMA and WCDMA besides the tele communication systems using OFDM method with single terminal An intergrated system can be improved with adopting of SoC technique. For adopting SoC technique on the intergrated terminal, we have to solve the non linear problem of HPA(High Power Amplifier). Nonlinear characteristic of HPA distorts both amplitude and phase of transmit signal, this distortion cause deep adjacent channel interference. We adopt a polynomial pre-distortion technique for this problem. In this paper, a noble modem design for NG mobile communication service and a method using polynomial pre-distorter with PAPR technique for counterbalancing nonlinear characteristic of the HPA are proposed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.6
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• pp.1302-1308
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• 2005

Propose Cellular-IP/PRC network with united paging and Cellular IP special duality that use roof information administration cache to secure lake acceptance method in wireless Internet environment and QoS in lesser extent cell environment. When speech quality is secured considering increment of interference to receive in case of suppose that proposed acceptance method grooves base radio station capacity of transfer node is plenty, and moat of contiguity cell transfer node was accepted at groove base radio station with a blow, groove base radio station new trench lake acceptance method based on transmission of a message electric power estimate of transfer node be. Do it so that may apply composing PC(Paging Cache) and RC(Routing Cache) that was used to manage paging and router in radio Internet network in integral management and all nodes as one PRC(Paging Router Cache), and add hand off state machine in transfer node so that can manage hand off of transfer node and Roaming state efficiently, and studies so that achieve connection function at node. Analyze benevolent person who influence on telephone traffic in system environment and forecasts each link currency rank and imbalance degree, forecast most close and important lake interception probability and lake falling off probability, GoS(Grade of Service), efficiency of cell capacity in QoS because applies algorithm proposing based on algorithm use gun send-receive electric power that judge by looking downward link whether currency book was limited and accepts or intercept lake and handles and displays QoS performance improvement.

• Cartoon and Animation Studies
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• s.35
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• pp.181-208
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• 2014

Kon Satoshi is a representative animation film director who explores human's intrinsic self-identity based on ambivalence and delivers a message for self-reflection of entity. The aim of this study is to analyze the persona of character according to the way how a self incorporates with another self in his film; that is to say, how a mask of the personality expresses and realizes itself from the perspectives of the Jung's analytical psychology. The persona, defined as the upmost external personality, involves social behavior playing a specific role to establish constant relationship with others in a society. With increasing demand in a society, individuals get to adapt to outer environment by playing his/her given role in various masks of personality. In this way, although persona acts as a major function in relationship with outer world, it would exert a negative influence on formation of self-identity because of the inconsistency between consciousness and unconsciousness when immersed only in mask of personality, complying excessively with the demand of group. However, persona does not always have a negative effect on relationships. Developed adequately to fulfill its social function, persona is helpful to establish a healthy self-identity with balanced control between inner world of unconsciousness and outer world of consciousness. From these perspectives, this study can identify how the desire of mask hidden inside of each character expresses to function in a positive or negative way by analyzing characters in the film according to integrated pattern and correlation between consciousness and unconsciousness. Additionally, I hope that the psychological research methods in this study will be full of help for interpreting on a character analysis as a theoretical approach.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.8
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• pp.1309-1321
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• 2008

Military style is not limited to a single period but represents various image communications related to items, synthetic images and different periodical culture backgrounds. The purpose of this study is to define the communicational function of the military style beginning from the 1st world war up to the modern days, and furthermore explain the characteristics and contents of military styles in different periods by studying the nowadays various symbols of the military style in denotative and connotative aspects. The research method is documentary studies through the literature and academic paper, and examined masters' and doctors' thesis, domestic and overseas books and fashion magazines, photographs and materials collected from the internet. As a result, first, the military style is a significant fashion code in understanding modern fashion by serving as a strong communication function representing people’s ritual through various image items called the 'military look'. Second, the meaning of the image communication through military look changed throughout the different periods. During the 1st and 2nd World war the military look supported Fascism by serving as a media representing extreme patriotism and at the same time social images like functionalism, women liberation, regulation and saving. During the cold war period it was used by young progressives like hippies and punks to send an opposing message towards war and commercialism. Since then up to the 80s it was a medium representing the ‘new role of women’, who possess same social rights and power as the men. However in the 90s the military style had to go through a paradigm transition period. Since this period it got affected by the post modernism and designers, consumers alike adopted military style to create unique beauty It can also be said that it began to be used as a pure fashion code representing intertextuality. It was rather expressed as a metonymy than a metaphor and combined with elegance and feminine factor, which contrasts to the original military concept, it now represents totally new hybrids such as difference, dissemination and varieties.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.12C
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• pp.1265-1275
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• 2002

In the network management system, there are two approaches; the centralized approach based on SNMP and the distributed approach based on mobile agent. Some information changes with time and the manager needs to monitor its value in real time. In such a case, the polling is generally used in SNMP because the manager can query agents periodically. However, the polling scheme needs both request and response messages for management information every time, which results in network traffic increase. In this paper, we suggest an adaptive network monitoring method to reduce the network traffic for SNMP-based network management. In the proposed strategy, each agent first decides its on monitoring period. Then, the manager collects them and approves each agent's period without modification or adjusts it based on the total traffic generated by monitoring messages. After receiving response message containing monitoring period from the manager, each agent sends management information periodically without the request of manager. To evaluate performance of the proposed method, we implemented it and compared the network traffic and monitoring quality of the proposed scheme with the general polling method.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.241-247
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• 2016

As a domestic traffic control signal system, either the system with which a traffic signal turns into green at regular intervals or the system with which an amber or a red signal flickers on local roads without heavy traffic at midnight has been utilized. However, when the former system is used for roads with light traffic at midnight, delays and congestion can be incurred. Besides, in case of the latter signal system, the risk of vehicle crash is high. This study proposes a response type of flickering green signal system that rearranges signal system after analyzing beacon messages including sensor data. The proposed system, on a trunk road or a branch road at midnight, makes the signal keep flickering in green; When a vehicle enters the range of RSE, the transfer coverage, it transmits beacon messages regularly and Agent System analyzes the messages and alters the signal. It is a system by which vehicles move following the altered signal system, which will not only ensure smooth flow but also prevent vehicles from crashing on a road with light traffic. As a result of a simulation, traffic throughput and the average waiting time displayed 10 to 30 percent better improvement than existing signal systems, in terms of performance.

• The Journal of the Korea Contents Association
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• v.15 no.2
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• pp.151-162
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• 2015

A theme park is a complex space, in which held is a performance & exhibition event created to make visitors feel fun and a deep impression through a certain theme. Recently, local governments are increasingly planning for theme parks with the aim of local economy revitalization. Accordingly, this paper set up a development model for a Korean culture theme park after deducting success factors for creating a successful theme park through the case of Korean culture theme park. To be concrete, this paper deducted the success factors through literature research and case research as follows: Setting of themes having identity and consistency; programs that can give fun and a deep impression; convenient support facilities reflecting customers' needs; differentiated marketing for progress in customer attraction power; location linked with cultural resources around a theme park and a space for communicating a message; privately-initiated project promotion and the main body of operation; target setting consequent on market segmentation, and demand forecast, etc. A theme park cannot be successfully operated to contribute to local economy revitalization until such success factors should be closely linked and harmonized with each other. In addition, in order for a theme park to make a continued growth, it's required that problems occurring at the operational stage should be endlessly improved, and contents strengthening should be continuously done in line with circumstances of the times and viewers' eye level.