• Journal of the Ergonomics Society of Korea
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• v.23 no.2
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• pp.105-120
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• 2004

With the new technology and the popularization of mobile phone. the functions and designs of mobile phone have been varied rapidly. However. based on the user's level of familiarity on mobile phone function and knowledge of information technology. the using behaviors of mobile phone. especially between the young users who are well acquainted with the latest function and technology and the over middle-aged users who are relatively not. would be quite different. A survey was conducted to investigate the various using behaviors of mobile phone in different age groups. The total number of six hundred and sixty-seven people from age seventeen to sixty participated in this study. The participants were divided into young group (age between 17 to 29) and the over middle-aged group (age between 40 to 60) to compare the difference group considered design. price. and function of the mobile phone as three important factors. on the other hand. the over middle-aged group considered quality of communication. price and ease of use as three important factors. All the respondents of the young group know how to use the text messaging function. however for the over middle-aged group. 40% of the respondents knows how to use the text messaging function. The over middle-aged group seemed mainly use the mobile phone for voice communication. however the young group had a tendency to communicate each other with short text message rather than through voice conversation. Twenty percentage of young group responded that they had an experience of pain or discomfort at the thumb. the thenar eminence area. or carpus area during pushing the mobile phone keypad. The excessive frequent use of keypad may cause the risk of repetitive strain injury (RSI). The results of this study could provide important information to understand the way of using mobile phone in different age groups. and also could be used to design and market the mobile phone.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.10
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• pp.2357-2375
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• 2013

Message ferry is a controllable mobile node with large capacity and rechargeable energy to collect information from the sensors to the sink in wireless sensor networks. In the existing works, route of the message ferry is often designed from the solutions of the Traveling Salesman Problem (TSP) and its variants. In such solutions, the ferry route is often a simple cycle, which starts from the sink, access all the sensors exactly once and moves back to the sink. In this paper, we consider a different case, where the ferry route is a closed walk that contains more than one simple cycle. This problem is defined as the Closed Walk Ferry Route Design (CWFRD) problem in this paper, which is an optimization problem aiming to minimize the average weighted delay. The CWFRD problem is proved to be NP-hard, and the Integer Linear Programming (ILP) formulation is given. Furthermore, a heuristic scheme, namely the Initialization-Split-Optimization (ISO) scheme is proposed to construct closed walk routes for the ferry. The experimental results show that the ISO algorithm proposed in this paper can effectively reduce the average weighted delay compared to the existing simple cycle based scheme.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.43-49
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• 2012

Personalized message syndication is an important process for maximizing the effect of mobile marketing. This paper proposes an algorithm for determining clients satisfying target conditions in real-time. The proxy server as an intermediate node stores client profiles (gender, age, location, etc) and their respective summaries into a database. When a company syndicates messages at run time, the proxy server maps target conditions expressed by boolean expressions to integer value and determines target clients by comparing target value with profile summary. Thus, this approach provides efficient personalized message syndication in very large systems with millions of clients because it can determine target clients in real-time and work with a traditional database easily.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.7
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• pp.271-276
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• 2014

Short message service(SMS) in a mobile communication environment is a very convenient method. However, it caused a serious side effect of generating spam messages for advertisement. Those who send spam messages distort or deform SMS sentences to avoid the messages being filtered by automatic filtering system. In order to increase the performance of spam filtering system, we need to recover the distorted sentences into normal sentences. This paper proposes a method of normalizing the various types of distorted sentence and extracting keywords through automatic word spacing and compound noun decomposition.

• Journal of Communications and Networks
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• v.17 no.5
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• pp.499-505
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• 2015

We analyze the performance of multistage cooperation in decode-and-forward relay networks where the transmission between source and destination takes place in $T{\geq}2$ equal duration and orthogonal time phases with the help of relays. The source transmits only in the first time phase. All relays that can decode the source's transmission forward the source's message to the destination in the second time phase, using a space-time code. During subsequent time phases, the relays that have successfully decoded the source message using information from all previous transmitting relays, transmit the space-time coded symbols for the source's message. The non-decoding relays keep accumulating information and transmit in the later stages when they are able to decode. This process continues for T cooperation phases. We develop and analyze the outage probability of multistage cooperation protocol under orthogonal relaying. Through analytical results, we obtain the near-optimal placement strategy for relays that gives the best performance when compared with most other candidate relay location strategies of interest. For different relay network topologies, we also investigate an interesting tradeoff between an increased SNR and decreased spectral efficiency as the number of cooperation stages is increased. It is also shown that the largest multistage cooperation gain is obtained in the low and moderate SNR regime.

• Smart Media Journal
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• v.4 no.3
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• pp.24-30
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• 2015

For suddenly encountered emergencies, most people embarrass, and can not often deliver the correct message when they report. Recently in the commonplace smart software environment, it is important that they can transmit the correct individual emergency situation efficiently and can receive the best service, and can provide the efficient emergency medical services to real-time around the other emergencies. In this paper, we design a standard protocol for the rapid and accurate technology for transmitting XML-based structured messages to provide an efficient emergency medical services, and offers a emergency medical services protocol to make them available more efficiently.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.4
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• pp.9-17
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• 2020

When IoT sensor nodes are deployed in areas where data collection is challenging, sensors must be relocated if sensing holes occur due to improper placement of sensors or energy depletion, and data collection is impossible. The sensing hole's cluster header transmits a request message for sensor relocation to an adjacent cluster header through a specific relay node. However, since a specific relay node is frequently used, a member sensor located in a specific cluster area adjacent to the sensing hole can continuously receive the movement message. In this paper, we propose a method that avoids the situation in which the sensing hole cluster header monopolizes a specific relay node and allows the cluster header to use multiple relay nodes fairly. Unlike the existing method in which the relay node immediately responds to the request of the header, the method proposed in this paper solves a ping-pong problem and a problem that the request message is concentrated on a specific relay node by applying a method of responding to the request of the header using a timer. OMNeT++ simulator was used to analyze the performance of the proposed method.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.2
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• pp.75-82
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• 2008

Mobile IP was proposed to overcome identity problem of original IP address system caused by mobility of wireless mobile host. To complete its network handoff procedure, it must receive a mobile advertisement broadcasted by mobile agent. Generally, in a mobile IP system, mean time delay, 500ms, in a network handoff procedure is a critical problem of wireless service such as Voip, multimedia streaming. A caching agent caches a latest mobile advertisement, and replays it by receiving solicitation message from a mobile node finishing link layer detection. But, during the procedure of mobile registration, many packets from service provider to the mobile host would be lost and handoff time delay would be increased. In this thesis, we propose an unproved caching agent technique which can forward data packets while handoff procedure, and CoA pool for fast mobile IP registration.

• Journal of the Korea Society of Computer and Information
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• v.13 no.3
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• pp.161-168
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• 2008

A standard Web server or web application servers require the Web Servlet container to execute SOAP messages. But it requires additional process to make web service modules and need communication port. Also, Recently many web applications is becoming increasingly demand against the dynamic document than the static documnet. But a recent study has found that Apache Web Server always does not show the better performance. The more it have the dynamic documents, rather it can show worse performance. To solve this problem, we propose a new High-Speed Message Processing System, in which the SOAP_MP and the WSDL builder are used. The WSDL builder convert HTML/XML to WSDL files automatically and the SOAP_MP minimize SOAP massage processing time by eliminating the Tomcat Servlet container in the mobile Web Services implementation. We compare and analyze the System, which was proposed by us, with the standard Web Service system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.11
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• pp.2849-2865
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• 2012

In order to block mobile junk messages automatically, many studies on spam filters have applied machine learning algorithms. Most previous research focused only on the accuracy rate of spam filters from the view point of the algorithm used, not on individual user's preferences. In terms of individual taste, the spam filters implemented on a mobile device have the advantage over spam filters on a network node, because it deals with only incoming messages on the users' phone and generates no additional traffic during the filtering process. However, a spam filter on a mobile phone has to consider the consumption of resources, because energy, memory and computing ability are limited. Moreover, as time passes an increasing number of feature words are likely to exhaust mobile resources. In this paper we propose a spam filter model distributed between a users' computer and smart phone. We expect the model to follow personal decision boundaries and use the uniform resources of smart phones. An authorized user's computer takes on the more complex and time consuming jobs, such as feature selection and training, while the smart phone performs only the minimum amount of work for filtering and utilizes the results of the information calculated on the desktop. Our experiments show that the accuracy of our method is more than 95% with Na$\ddot{i}$ve Bayes and Support Vector Machine, and our model that uses uniform memory does not affect other applications that run on the smart phone.