• The KIPS Transactions:PartC
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• v.16C no.1
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• pp.51-56
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• 2009

Time synchronization algorithm in wireless sensor networks is essential to various applications such as object tracking, data encryption, duplicate detection, and precise TDMA scheduling. This paper describes CDRS that is a time synchronization algorithm using the Clock Drift rate and Reference Signals between two sensor nodes. CDRS is composed of two steps. At first step, the time correction is calculated using offset and the clock drift rate between the two nodes based on the LTS method. Two nodes become a synchronized state and the time variance can be compensated by the clock drift rate. At second step, the synchronization node transmits reference signals periodically. This reference signals are used to calculate the time difference between nodes. When this value exceeds the maximum error tolerance, the first step is performed again for resynchronization. The simulation results on the performance analysis show that the time accuracy of the proposed algorithm is improved, and the energy consumption is reduced 2.5 times compared to the time synchronization algorithm with only LTS, because CDRS reduces the number of message about 50% compared to LTS and reference signals do not use the data space for timestamp.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.8
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• pp.517-526
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• 2013

When developing an android mobile application the androids intent is used as a mechanism to send messages between local equipment of androids application inner part and other applications. But the androids intent does not support sending messages via each android products intent. If there is a way to support each androids equipments to send messages, it will be easier to make non-stopping services. Non-stopping service is used when the user is using the android to do word or searching services and suddenly changes to a different android product but still maintains the progress what was currently being done without waiting the programs to be loaded. It is possible to send messages to each android products by using the socket, but the connection must be maintained stably which is the weak point. In this paper, I am suggesting a BRIF(Broadcasting Remote Intent Framework) framework to send messages to different android products. BRIF is a framework that uses the Googles C2DM service which services asynchronous transmissions to different android products. This is organized with the C2DM server, RemoteContext Api, web server and RISP(Remote Intent Service Provider) which is will be easy to be used for the developers since there are no big changes for coding compared to the intent code.

• Management & Information Systems Review
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• v.31 no.3
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• pp.47-73
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• 2012

SNS allowed users to serve not only as the content and message producer but as the consumer, with development into various types of SNS platforms. Instead of a traditional media structure of media-to-many and unspecified users, it also made it possible to achieve one-to-one or one-to-many interactions, regardless of time and space, through SNS platforms. Moreover, according to development of digital communication technology, IT, media contents and communication network have been mutually connected, though they were once separate. The changes in communication environments have caused rapid disorganization and reorganization in popular culture led by specific expert groups. Such trend has a greater influence on marketing strategies of enterprises. In other words, it will lead them to mostly introduce new information technologies, based on consumer market, and to strategically participate in SNS for promotion and marketing for their products and brands. Likewise, SNS has currently appeared as the main media affecting consumers' behaviors. In consideration of the importance of SNS features, which can stimulate responses of other users, analysis of main features affecting SNS user acceptance decision is required, as well as its utilization strategies. Accordingly, this study conducted division of SNS features into openness, quickness, interactiveness and economical efficiency to derive strategies for increasing the usage frequency of SNS and ultimately maximizing the expectation effect, in addition to an empirical analysis of effects of SNS features on usefulness, easiness and pleasure perceived in SNS, and SNS user intention.

• Journal of Digital Convergence
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• v.8 no.2
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• pp.69-87
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• 2010

This research is to investigate phatic communication by puting the purpose in maintaining and strengthening social relationship among people in groups in Korean residential community space. Phatic communication is the activity for friendship, expressing and sharing the tastes, expectations, and common features of residents by inducing the participation of residents in all sorts of events, meetings, and activities in residential space. Through this pathic activity, the range of communication age, the time of communication, the selection of location, and the topic of communication discourse are examined. The investigation methods of this research were taken two ways: First, it carried out the observation of participation and in-depth interview by the participation of researcher in a way of life as a member. In order to prove more objectively, it enhances the reliability of data by adding the questionnaire survey through the convenience sampling of 150 residents of three communities. Moreover, $x^2$; chi-square test was conducted in order to verify the difference in heterogeneous groups. Accordingly, this research will bring about the great development in cultural studies by exploring a way of Korean life, based on the communication of Korea community in residential life space, which can unify the community through sharing the meaning, interacting and delivering the message.

• Journal of the Ergonomics Society of Korea
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• v.30 no.3
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• pp.403-408
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• 2011

The purpose of this study was to investigate the effects of the secondary tasks such as sending text message(STM) and searching navigation(SN) on vehicle speed and distance during driving and brake response time during unexpected situation using a driving simulator. The participants included 19 college students; 9 males aged $25.2{\pm}1.0$ with $2.4{\pm}2.0years$ of driving experiences and 10 females aged $21.4{\pm}0.5$ with $1.3{\pm}0.5years$ of driving experiences. All subjects were instructed to keep a certain distance(30m) from the car ahead and a constant speed(100km/h). Average speed and average following distance were measured during 10 seconds before unexpected situation. Also, brake response time after unexpected situation was measured. Average speed was more decreased and average following distance was more increased during the driving with secondary tasks than driving only. Male maintained the assigned speed and distance better than female. The brake response time was faster during driving only than the driving with secondary tasks. And the brake response time of male was shorter than that of female.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2D
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• pp.227-235
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• 2011

At present, the characteristics of drivers are not properly considered when informations are provided via VMS even though the Variable Message Signs(VMS) are one of the key information provision medias on the roads. In this study, the driver's psychological response(stress index) was evaluated using a driving simulator for the position of the VMS provided, the contents of the VMS provided, the size of characters on VMS, and types of VMS expression. It was appeared that the stress is the least when the position of the VMS provided 1.5km proceeded from exit, the contents of the VMS provided are time information and types of VMS expression are character form respectively and the size of characters on VMS is appeared not important. In addition, the change of the users' satisfaction level was measured when increasing the numbers of VMS on unit distance and the size of characters. The size of character was almost not effected in similar to the result of stress index and the satisfaction level increased when increasing the number of VMS on the unit distance. The results of this research can be utilized as basic data for the ITS system design and operation stages.

• Journal of the Korea Society of Computer and Information
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• v.18 no.1
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• pp.63-71
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• 2013

In the Cluster-Based Routing Protocol (CBRP) a cluster header in each cluster should be elected. The cluster headers consume energy much more than other member nodes do because they manage and operate all of mobile nodes in their cluster. The traditional CBRP elects a cluster header without considering the remaining electric energy of each node. So, there exist problems that the cluster header has short average lifetime, and a new cluster header should be elected again frequently. In this paper, we propose the improved protocol which prolongs the lifetime of the cluster header, decreases the problem of re-electing the cluster header and enhances the stability of the path. In order to achieve this, when a cluster header is elected in a cluster, the remaining electric energies of all the nodes are compared with one another, and the node with the highest energy is elected as the cluster header. Also, the node with the second highest energy is elected as the second header. If the elected cluster header is unable to perform the role of the cluster header any more because the remaining energy level goes low, it sends a beacon message to neighbor member nodes, then the second header will serve as the cluster header.

• The Korean Journal of Zoology
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• v.38 no.4
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• pp.550-556
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• 1995

The c-myc proto-oncogene is Involved In the control of normal cell proliferation and differentiation of many cell lineages. Although it has heen suggested that c-myc may play an important role in the mammalian early development, it Is unclear whether the embryonic c-myc mRNA is originated from zygotic gene expression or stored maternal message. Thus, we have construded expression vectors, In which the 5, flanking sequences including c-myc promoter region and a large non-coding exon I are fused 'sith E. coli lacZ gene that encedes $\beta$-galactosldase as a reporter. As c-myc exon I contains a modulatory sequence, we designed t, vo types of vectors (pcmyc.Gall and pcmyc-Ga12) to examine the role of exon I in c-myc expression. The former contains the complete exon I and the later has a deletion in 40 bp of modulator sequence located In the exon I of c-myc These vectors were microInjected into fertilized one-cell embryos and $\beta$-galactosidase activity was examined by X-gal staining during early embryogenesis. $\beta$-galactosidase activity derived from c-myc promoter was decreased at two-cell stage. The expression level directed by pcmyc- Ga12 was similar to that of pcmyc-Gal1, indicating that the medulatory sequence in exon I may not be Involved at least In the regulation of embryonic c-myc expression. In summary, the present study indicates that the c-myc promoter is functional at the early stage embryo, and the regulation of c-myc expression is under the control of "zygotic" clock of preimplantation mouse embryos.e embryos.

• Korean Business Review
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• v.17 no.2
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• pp.203-228
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• 2004

This dissertation investigated the evaluation model of IT Service quality: concentrated on the quality components in mobile communication service. Today, mobile communication service is changing dramatically. The first and second generation's mobile communication services were designed for voice and SMS(Short Message Service). However, while the mobile communication industry grows, the mobile technology made more services available for customers. Customers' changing needs brought a new opportunities to the market. Now, mobile communication service is facing a new era as multi-functioning, multimedia service, and high speed data transfer service are being introduced. There has been a lot of theoretical literature on service quality components of mobile communication, but most of the literature was focused on the voice service and SMS(1st and 2nd generation). As mobile communication service evolves, the components may have to be altered or rebuilt. To identify which service quality components ought to be utilized, prior studies on service quality components, service quality, and customer satisfaction were reviewed. Also, a survey was conducted on the various aspects of mobile communication service. This study suggests 6 components of service quality: those are supporting facilities, cellular phone(facilitating goods), quality of the voice service(explicit service), supplementary services, supporting services, and cost. Empirical results supported that all of these components are proven as the service quality components, but, with regards to customer satisfaction, only cellular phone(facilitating goods) and supplementary services are effective. As previously stated, the relationship between service quality and customer satisfaction is also proven. This study is a point of departure for the success of upcoming generation's mobile communication service. It identifies what is valuable from the customer's point of view. Furthermore, it suggests some ideas to prepare for future market opportunities.

• The Journal of Bigdata
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• v.1 no.1
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• pp.67-75
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• 2016

The study analyzed big data extracted from Google and social media to identify factors related to searches on cyber bullying in Korea and America. Korea's cyber bullying analysis was conducted social big data collected from online news sites, blogs, $caf{\acute{e}}s$, social network services and message for between January 1, 2011 and March 31, 2013. Google search trends for the search words of stress, exercise, drinking, and cyber bullying were obtained for January 1, 2004 and December 22, 2013. The main results of this study were as follows: first, the significant factors stress were cyber bullying that Korea more than America. Secondly, a positive relationship was found between stress and drinking, exercise and cyber bullying both Korea and America. Thirdly, significant differences were found all path both Korea and America. The study shows that both adults and teenagers are influenced in Korea. We need to develop online application that if cyber bullying behavior was predicted can intervene in real time because these actual cyber bullying-related exposure to psychological and behavioral characteristic.