• The Journal of the Korea Contents Association
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• v.18 no.5
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• pp.514-524
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• 2018

The purpose of this study was to investigate learners' reaction behaviors by the type of learning motive when teaching messages were delivered. The subjects of this study were 82 students from Auniversity and Buniversity in the metropolitan area. Students were online collaborative learning. The instructor delivered six messages. Since then, the researchers have measured the learner 's response time and the frequency and level of interaction. And analyzed using an independent sample t-test. As a result, the frequency and level of interaction increased before the message was delivered. The response time to instructional messages was the fastest among the students with performance avoidance goal orientation. Mastery goal orientation students were most sensitive to scaffolding messages. Performance avoidance goal orientation students responded most sensitively to the reminder message. Finally, Mastery goal orientation students had the most action on new topics. And performance approach goal orientation students had the most to do with accuracy and relevance.

• Journal of Advanced Navigation Technology
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• v.10 no.2
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• pp.120-127
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• 2006

Data-caching of a client is an important technology for interaction with a server where data are cached and operated at the client node. Caching reduces network latency and increases resource utilization at the client. In a Client-server environment, the absence of cache consistency algorithm, we cannot guarantee the correctness of client applications. In this paper, we propose a new asynchronous avoidance-based cache consistency algorithm. We remove the additional callback due to the lock escalation in AACC. With a comprehensive performance analysis, we show that the proposed algorithm has less message exchange than the AACC. One-copy serializability is used for proving correctness of the proposed algorithm.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.3
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• pp.252-258
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• 2010

If the speed measurement of resolver and the generation of PWM signals are implemented with single microcontroller, it is easy to reduce the system cost and to avoid the switching noise of inverters. To avoid the switching noise and to improve the accuracy of measurement, PWM switching and A/D sampling of the resolver should be synchronized. Phase angle of the resolver excitation signal is increased in stepwise manner, then, the output signal of the resolver is measured in each step. From the measured data, the optimal phase angle of resolver excitation signal is estimated using the least square approximation method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.6C
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• pp.572-579
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• 2010

Filtered multi-tone (FMT) is a form of multicarrier modulation utilizing frequency-domain equalization efficient in multi-path fading channels. Doppler frequency information can be employed for channel estimation and link adaptation to improve the performance. However, most previous studies have concentrated on the orthogonal frequency division multiplexing (OFDM) instead of FMT. Moreover, they have not considered the synchronization error that can commonly occur in practical systems. In this paper, we propose Doppler frequency estimation scheme that is effective in FMT systems with residual synchronization error and high noise levels.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.8C
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• pp.667-679
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• 2010

The use of femtocells in buildings and homes has been widely studied as a means to enlarge the cell coverage and increase the network capacity of mobile communication systems. Femtocells for Mobile WiMAX (M-WiMAX) using time division duplexing (TDD) requires frame synchronization with neighboring base stations to avoid interference between uplink and downlink signals. In this paper, we propose a new frame synchronization method for femtocell using IEEE 802.11 based wireless backhaul, which transfers the time information of mobile network to femtocells via the beacon signal provided by IEEE 802.11. Also, in order to reduce timing error of the proposed method, we modify the collision avoidance scheme in the transmitter of IEEE 802.11 and apply a timing estimation technique designed in the sense of least squares to the receiver of IEEE 802.11. Through computer simulations using the proposed scheme, we evaluate the performance of frame synchronization for femtocells and show that the recovered timing information satisfies the timing specification defined by M-WiMAX standard.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.699-713
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• 2013

This study has three purposes. Firstly, we try to extract the types of the motives of OCBO & OCBI instead of global OCB. Secondly, we compare the types of the motives OCBO & OCBI and those of the motives of global OCB. Finally, using another set of P-sample, we try to find out whether the four types of the motives of OCB found in the study of Kim & Lee(2013) could be found once again. The findings are as follows. First, we found the four types of the motives of OCBO, and three the types of the motives of OCBI. Second we found some similarities and differences at the same time between the types of OCBO, OCBI, & global OCB. Third, except the instrumentality-based type, three of the four types found in the study of Kim & Lee(2013) reappeared in this study. In conclusion, these findings suggest that OCBO & OCBI, the sub-dimensions of OCB, have their own distinctive natures respectively.

• Journal of dental hygiene science
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• v.12 no.4
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• pp.375-382
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• 2012

This research will target the Dental Hygienics students to identify the level and type of the $2{\times}2$ achievement target orientation, and will study how this achievement target orientation is related to the Self-Regulated Learning, as well as the effect on the each sub elements of the Self-Regulated Learning (SRL). Among the $2{\times}2$ achievement target orientation of all the female university students, the skillful approach was found to be highest. In case of the adjustment of the motivation following grade, intrinsic value of the 1st grader was higher than the intrinsic value of the 2nd and 3rd graders. As for the behavior adjustment, the 3rd grader's time and studying adjustment were found to be higher. Mean while, pursuit of the cooperation was found to be high compared to the time and studying adjustment of the1st and 2nd graders. Second, intrinsic value, overt goal orientation, and studying environment adjustment among the SRL's subelements, manifested significant correlation with all the sub elements of the $2{\times}2$ achievement target orientation. As for the elements that affected cognition adjustment, grade and skillful approach were found to exert significant effect on the performance adjustment. As for the element that affects behavior adjustment, grade and skillful approach exerted significant effect on the sub elements of the behavior adjustment. Analysis on the effect of the achievement target orientation and SRL implies that the direction of the students' learning goal can be modified and that they can learn effectively by using the SRL appropriately. When the two elements are factored in carefully, the key findings could serve as a base data that can motivate the students, inducing effective learning process.

• Journal of the Korea Society for Simulation
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• v.20 no.4
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• pp.1-11
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• 2011

In the development phase of a torpedo, the effectiveness analysis is carried out to predict the performance and to learn how to use the torpedo. In order to obtain reliable data, it is required to model the tactical situation closely to the actual one. Because the submarine is a target of a lightweight torpedo, the anti-torpedo countermeasures of a submarine such as evasive maneuvering and TACM (Torpedo Acoustic Counter Measure) should be modeled in detail. In this paper, the evasive maneuvering is modeled reflecting the movement characteristics of the submarine. Furthermore various TACMs such as a floating-type decoy, a self-propelled decoy and jammers are also modeled. Then, effectiveness of a lightweight torpedo is measured and analyzed using the simulation program which is developed through the above modeling procedure.

• Journal of the Korea Society of Computer and Information
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• v.25 no.3
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• pp.163-168
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• 2020

In this paper we propose a The purpose of this study was to examine the psychological characteristics of youth mobile phone use. Internally, we want to find out about self-regulation, interpersonal relationship, pleasure, and desire to achieve reality. For the research, the Korea Information Society Agency utilized 568 data based on self-control and user motivation among long-term tracking data of Internet and mobile phone addiction in 2018. The SPSS window 23 version was used for data analysis, and the data collected were analyses to identify the subject's demographic characteristics. In addition, the correlation of variables between groups was investigated by analyzing dummy variables, and the results of the study were as follows. First, the addiction was slightly higher in mobile phone game groups than in social network service (SNS) groups, but in the same period of use, social network service (SNS) groups showed a higher desire for interpersonal relationships. In the desire to avoid reality, mobile phone game groups showed a higher gap than social network service (SNS) However, there was no difference between groups in terms of pleasure and desire to achieve. The results of this study indicated that the content of mobile phone use differed in factors affecting mobile phone overuse, and suggestions for follow-up research were discussed.

• The Journal of the Korea Contents Association
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• v.22 no.8
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• pp.106-114
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• 2022

This study attempted to empirically investigate the difference in the Advertising Acceptance Attitudes of pre-roll advertisements according to the Use Motivation and Use Intensity of YouTube, which act as important factors in using YouTube. For this study, a survey targeted to both male and female university students was conducted, 200 people's data being used for the analysis. First research result was that positive attitude towards advertisement based on the Youtube Use Motivation was higher for the group who pursue narrative identities than the group who habitually use intention and pursue amusement. For avoidance behavior, the group who habitually use intention and pursue amusement was higher than the group who pursue narrative identities. Second, for the positive attitude towards advertisement based on Youtube Use Intensity, the group with higher Use Intensity showed an optimistic attitude relative to the group with lower Use Intensity. However, there was no difference in the avoidance behavior for advertisement. These following results imply that a strategy considering the Use Pattern based on the Use Motivation and Use Intensity of the users is needed in enforcing YouTube pre-roll advertisements.