• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.8
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• pp.2814-2832
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• 2014

As information society matures to an even higher level and as information technology becomes a necessity to our everyday lives, the needs to develop, support and satisfy personal and social needs without the limitation of time, space, and location have become a vital point to everyday lives. Smartphone users are increasing at a staggering rate but the research on mobile-Learning model and the implementation of m-Learning scenario are still behind the needs of the users. Therefore, this paper focuses on the design of 'repeatable and short-spanned m-Learning model' to meet the needs of the learners who are on the go and on the move with their smartphones. Smartphone users frequently reach out for their phones but compare to the frequencies, the actual span of time they spend per use are relatively and surprisingly short. One way to understand this phenomenon is that the users tend to immediately replace their smartphones with laptops or desktops whenever they are available. A leaning model was needed to reflect this short and frequent use, a use that is solely based on the smartphone environment. This proposed learning model first defines this particular setting and implements the model to real smartphone users over an 8 week period. To understand whether different learning backgrounds can influence this model, different schools with online and offline learning channels participated in the experiment. User survey was conducted after the experiment to get a better understanding of the smartphone users. Pretest and posttest were conducted before and after the experiment and the data were validated and analyzed using SPSS version 18.0 for PC. Preliminary descriptive statistics, multiple regression and cross validation was conducted for the analysis. The results showed that the proposed English Listening and Comprehension Mobile Digital Textbook (ELCMDT) had a positive effect on the learners in general and was more effective for learners who were already experienced with online learning.

• Korean Journal of Artificial Intelligence
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• v.7 no.1
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• pp.23-59
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• 2019

The purpose of this study is to develop a measure of service quality in the traditional market by examining previous research on the service quality of the traditional market studied so far. After defining basic concepts through definition of traditional market and existing studies, 5 categories of configuration items for SERVQUAL measurement in traditional market were made up based on existing researches related to definition of service quality and service quality of traditional market. A survey was conducted on the items that fit the intention of this study and various statistical analyzes were conducted. Statistical analysis was performed using SPSS 22.0 and AMOS 22.0. The reliability of the items was measured by the reliability test, and the predictability and accuracy of the items were examined. The validity of the measured variables was verified through confirmatory factor analysis. Reliability, empathy, responsiveness, certainty, and tangibility were the most important factors in this study. Responsiveness factors include communication, time reduction, real time, promptness. Assurance factors include the assurance of delivery, prompt answers, product knowledge items. Tangibility factors include, convenient device systems, location information, presence as a fact, and as a result, the latest modern items are adopted. The quality of service in the traditional market developed in this study was found to be good in reliability and validity test. Confirmatory factor analysis result using structural equation model also met the conformity index standard. If service satisfaction is measured based on this research, basic data can be presented to policy makers who implement policies on traditional markets to make the right decisions. In addition, it will be able to provide traditional market operators with operational strategy and marketing data. In the future, based on the traditional market service quality scale developed in this study, it is necessary to grasp the factors to be continuously managed to improve the service quality of the traditional market, user satisfaction, and intention to use.

• Journal of Korean Society of Transportation
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• v.23 no.8 s.86
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• pp.129-138
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• 2005

Since Successive introduction of BMS(Bus Management System) into the local governments has been able to collect each bus data on the road and valuate the bus operation by the quantitative index not qualitative index. we need a study on punctuality index for evaluation of service level for bus operation using bus location information. We propose punctuality index for bus operation using time-space diagram and valuate the index by application to real bus data.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.628-632
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• 2005

Remote sensing through atmospheric turbulence had been hard works for a long time, because wavefront distortion due to the Earth's atmospheric turbulence deteriorates image quality. But due to the appearance of adaptive optics, it is no longer difficult things. Adaptive optics is the technology to correct random optical wavefront distortions in real time. For past three decades, research on adaptive optics has been performed actively. Currently, most of newly built telescopes have adaptive optical systems. Adaptive optical system is typically composed of three parts, wavefront sensing, wavefront correction and control. In this work, the wavefront sensing technology for adaptive optical system is treated. More specifically, shearing interferometers and Shack-Hartmann wavefront sensors are considered. Both of them are zonal wavefront sensors and measure the slope of a wavefront. . In this study, the shearing interferometer is made up of four right-angle prisms, whose relative sliding motions provide the lateral shearing and phase shifts necessary for wavefront measurement. Further, a special phase-measuring least-squares algorithm is adopted to compensate for the phase-shifting error caused by the variation in the thickness of the index-matching oil between the prisms. Shack-Hartmann wavefront sensors are widely used in adaptive optics for wavefront sensing. It uses an array of identical positive lenslets. And each lenslet acts as a subaperture and produces spot image. Distortion of an input wavefront changes the location of spot image. And the slope of a wavefront is obtained by measuring this relative deviation of spot image. Structures and measuring algorithms of each sensor will be presented. Also, the results of wavefront measurement will be given. Using these wavefront sensing technology, an adaptive optical system will be built in the future.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.05a
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• pp.134-139
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• 2002

Fracture behaviors of pipes with local wall thinning are very important for the integrity of nuclear power plant. However, effects of local wall thinning on strength and fracture behaviors of piping system were not well studied. Acoustic emission(AE) has been widely used in various fields because of its extreme sensitivity, dynamic detection ability and location of growing defects. In this study, we investigated failure modes of locally wall thinned pipes and AE signals by bending test. From test results, we could be divided four types of failure modes of ovalization, crack initiation after ovalization, local buckling and crack initiation after local buckling. And fracture behaviors such as elastic region, yielding range, plastic deformation range and crack progress could be evaluated by AE counts, accumulative counts and time-frequency analysis during bending test. It is expected to be basic data that can protect a risk according to local wall thinning of pipes, as a real time test of AE.

• Journal of Korean Elementary Science Education
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• v.36 no.1
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• pp.1-15
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• 2017

The purpose of this study is to analyze the problems of land and sea breeze model experiment that has presented in $5^{th}$ grade curriculum in chapter "Weather and our lives" and makes better model simulation so that learners can have better and more effective way to study it. To survey the opinions from dedicated teachers about land and sea breeze model experiment, we produced the survey through interview with science exclusive teacher from M elementary school. An elementary science education expert, 3 men of science EdD modified and complemented survey and started Delphi survey to 12 science teachers who have career teaching more than 3 years. The problems found in this survey were 'one heat bulb, short heating time, small temperature difference of water and sand, lack of class time, empty space between sand and water, back of transparent boxes, little amount of scent and the location of the it' etc. But the most of all, it is hard to see the successful result of the experiment. Based on these kinds of investigations, and lots of trial and error, redesigned the new model experiment that has the most similarity to the real one and high probability of success. According to this, it was able to see the smoke forms horizontal movement along the sand and the smoke goes in one circulation cycle. through this experiment, we made a conclusion that although those scientific experiments in textbook were developed through lots of considerations of expert, to consider the aspect of consumer, it needs to reach the educational agreement about simulation experiment so that It can lead to successful experiment and high quality education.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.6
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• pp.357-364
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• 2014

In this paper deals with PON Remote monitoring solution using Reflecting Filter. The current FTTH-PON can not be monitored in real time that Optical cable fault and Quality degradation of Splitter. To solve this problem, Monitoring can make Feeder Network and Splitter that Reflecting filter development using the basic structure of Fiber Bragg grating. Reflecting Filter is Quality Monitoring System shall provide tools for user to view and analyze degradation of cables and splitter in particular predict any gradual component degradation(Optical cable bending, splice, connector, etc) before it becomes service impacting. The Reflecting Filter solution is splitter down and confirm the fault location of optical cable and it will send central control station can be monitored system an alarm to the OLT. In other words, wavelength side branches Mating existing communication affairs (Coupler) using the core of one optical wavelength for live monitoring two wavelengths and sends the subscriber side modem and aggregation switch device remotely using a reflective optical line filter monitoring the study of the system. this study can development of Reflecting filter improve the average processing time of Optical cable fault and efficient Maintenance of the network.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.5
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• pp.19-30
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• 2016

In these days, people get information from internet easily. However, there are too many information. It makes interrupt and inefficient for searching data. Therefore, we need user customized web search system which provides appropriate information. In this paper, we propose a searching system that can collect semi-automatically conditions of users such as weather, location and time and provide essential information to users. Using these context data, the proposed system can understand what information users want in specific situations and can provide more useful information to users than existing systems. The proposed system based on 'Production/Sharing Service of Personal Korean Contents with Voluntary Sharing Economy System' and we add data parsing algorithm in each input, store and search part. In the experiments, we compare and analyze the results of existing system and the proposed system using some general key words.

• Smart Structures and Systems
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• v.8 no.1
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• pp.119-137
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• 2011

A bio-inspired two-mode structural health monitoring (SHM) system based on the Na$\ddot{i}$ve Bayes (NB) classification method is discussed in this paper. To implement the molecular biology based Deoxyribonucleic acid (DNA) array concept in structural health monitoring, which has been demonstrated to be superior in disease detection, two types of array expression data have been proposed for the development of the SHM algorithm. For the micro-vibration mode, a two-tier auto-regression with exogenous (AR-ARX) process is used to extract the expression array from the recorded structural time history while an ARX process is applied for the analysis of the earthquake mode. The health condition of the structure is then determined using the NB classification method. In addition, the union concept in probability is used to improve the accuracy of the system. To verify the performance and reliability of the SHM algorithm, a downscaled eight-storey steel building located at the shaking table of the National Center for Research on Earthquake Engineering (NCREE) was used as the benchmark structure. The structural response from different damage levels and locations was collected and incorporated in the database to aid the structural health monitoring process. Preliminary verification has demonstrated that the structure health condition can be precisely detected by the proposed algorithm. To implement the developed SHM system in a practical application, a SHM prototype consisting of the input sensing module, the transmission module, and the SHM platform was developed. The vibration data were first measured by the deployed sensor, and subsequently the SHM mode corresponding to the desired excitation is chosen automatically to quickly evaluate the health condition of the structure. Test results from the ambient vibration and shaking table test showed that the condition and location of the benchmark structure damage can be successfully detected by the proposed SHM prototype system, and the information is instantaneously transmitted to a remote server to facilitate real-time monitoring. Implementing the bio-inspired two-mode SHM practically has been successfully demonstrated.

• Journal of Advanced Navigation Technology
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• v.20 no.6
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• pp.574-579
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• 2016

Unlike general unmanned aerial vehicles, the quad-rotor is attracting the attention of many people because of simple structure and very useful value. However, as the interest in drones increases, the safety and location of vehicles are becoming more important provide against aviation safety accidents or lost accidents. Therefore, in this paper, we propose a tracking system that stabilizes the model with a simple controller by linearized modeling and grasp tilt angle data from various sensor through the filter. The developed tracking system transmits the position of the quad-rotor in flight to the computer and shows it through the route, so it can check the flight path and various information such as flight speed and altitude at the same time. Then the sensor used in the actual quad-rotor can not measure exact sensor data for disturbance and vibration. So we use sensor fusion of Kalman filter and Complementary filter to overcome this problem and the stability of the quad-rotor hovering is realized by PID control. Through simulation, various information such as the speed, position, and altitude of the quad-rotor were confirmed in real time.