• Smart Structures and Systems
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• v.6 no.5_6
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• pp.481-504
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• 2010

Wireless smart sensor networks (WSSNs) have been proposed by a number of researchers to evaluate the current condition of civil infrastructure, offering improved understanding of dynamic response through dense instrumentation. As focus moves from laboratory testing to full-scale implementation, the need for multi-hop communication to address issues associated with the large size of civil infrastructure and their limited radio power has become apparent. Multi-hop communication protocols allow sensors to cooperate to reliably deliver data between nodes outside of direct communication range. However, application specific requirements, such as high sampling rates, vast amounts of data to be collected, precise internodal synchronization, and reliable communication, are quite challenging to achieve with generic multi-hop communication protocols. This paper proposes two complementary reliable multi-hop communication solutions for monitoring of civil infrastructure. In the first approach, termed herein General Purpose Multi-hop (GPMH), the wide variety of communication patterns involved in structural health monitoring, particularly in decentralized implementations, are acknowledged to develop a flexible and adaptable any-to-any communication protocol. In the second approach, termed herein Single-Sink Multi-hop (SSMH), an efficient many-to-one protocol utilizing all available RF channels is designed to minimize the time required to collect the large amounts of data generated by dense arrays of sensor nodes. Both protocols adopt the Ad-hoc On-demand Distance Vector (AODV) routing protocol, which provides any-to-any routing and multi-cast capability, and supports a broad range of communication patterns. The proposed implementations refine the routing metric by considering the stability of links, exclude functionality unnecessary in mostly-static WSSNs, and integrate a reliable communication layer with the AODV protocol. These customizations have resulted in robust realizations of multi-hop reliable communication that meet the demands of structural health monitoring.

• Journal of the Korea Society of Computer and Information
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• v.15 no.1
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• pp.1-12
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• 2010

Recently, processor performance has been improved dramatically. Unfortunately, as the process technology scales down, energy consumption in a processor increases significantly whereas the processor performance continues to improve. Moreover, peak temperature in the processor increases dramatically due to the increased power density, resulting in serious thermal problem. For this reason, performance, energy consumption and thermal problem should be considered together when designing up-to-date processors. This paper proposes three modified filter cache schemes to alleviate the thermal problem in the filter cache, which is one of the most energy-efficient design techniques in the hierarchical memory systems : Bypass Filter Cache (BFC), Duplicated Filter Cache (DFC) and Partitioned Filter Cache (PFC). BFC scheme enables the direct access to the L1 cache when the temperature on the filter cache exceeds the threshold, leading to reduced temperature on the filter cache. DFC scheme lowers temperature on the filter cache by appending an additional filter cache to the existing filter cache. The filter cache for PFC scheme is composed of two half-size filter caches to lower the temperature on the filter cache by reducing the access frequency. According to our simulations using Wattch and Hotspot, the proposed partitioned filter cache shows the lowest peak temperature on the filter cache, leading to higher reliability in the processor.

• Journal of the Korea Society of Computer and Information
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• v.25 no.6
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• pp.25-33
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• 2020

In this paper, the purpose is to verify the impact of performance expectations, effort expectations, social impact, individual innovation and perceived value on the intent of use and the behavior of use. Used Unified Theory of Acceptance and Use of Technology (UTAUT) to verify the applicability of this model in China, and established the research model by adding two new variables to UTAUT according to the situation of the Chinese market. To achieve this goal, 345 questionnaires were collected for experienced music creators using artificial intelligence nuggets in China by means of Internet research. The collected data were analyzed through frequency analysis, factor analysis, reliability analysis, and structural equation analysis through SPSS V. 22.0 and AMOS V 22.0. The verification of the hypotheses presented in the research model identified the decisive influence factors on the use of artificial intelligence music acceptance by Chinese users. The study is innovative in that it attempts to verify the applicability of UTAUT in the Chinese context. In the construction of the user acceptance model of AI music, three influencing factors will have an effect on users' intentions, and according to the degree of effect, from largest to smallest, they are respectively Perceived Innovativeness, Performance Expectancy and Effort Expectancy. This paper will also provide some management advices, i.e. improving the utility and usability of AI music, encouraging users with individual innovativeness, developing competitive and attractive pricing policies, increasing publicity, and prioritizing word-of-mouth advertising.

• Journal of Korean Society of Disaster and Security
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• v.14 no.2
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• pp.13-23
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• 2021

This study intended to assess the reliability of topographic data using satellite imaging data. The topographical data using actual instrumentation data and satellite image data were established and applied to the rainfall-leak model, S-RAT, and the topographical data and outflow data were compared and analyzed. The actual measurement data were collected from the Water Resources Management Information System (WAMIS), and satellite image data were collected from MODIS observation sensors mounted on Terra satellites. The areas subject to analysis were selected for two rivers with more than 80% mountainous areas in the Han River basin and one river basin with more than 7% urban areas. According to the analysis, the difference between instrumentation data and satellite image data was up to 50% for peak floods and up to 17% for flood totals in rivers with high mountains, but up to 13% for peak floods and up to 4% for flood totals. The biggest difference in the video data is Landuse, which shows that MODIS satellite images tend to be recognized as cities up to 60% or more in urban streams compared to WAMIS instrumentation data, but MODIS satellite images are found to be less than 5% error in forest areas.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.441-456
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• 2021

Enterprise is focused on R&D innovative activities in order to achieve sustainable growth & secure competitive advantage. There are many factors that influence enterprise innovation performance, but enterprise innovation activities do not always have a positive effect. Therefore, this study analyzed the effects of on innovation performance, focusing on innovation acceleration factors and innovation hindrance factors. The research model analyzed 2,081 national manufacturing enterprises that responded to the 2016 Korean Innovation Survey (STEPI). SPSS 25.0 was used to perform reliability, feasibility, and logistic regression analysis. The results are as follows. First, innovation activities have positive effects on enterprise product and process innovation performance. On the other hand, government support had the opposite results. Second, the collaboration of technology showed a positive effect on product innovation performance, independent of innovation acceleration and hindrance factors. Third, innovation activities showed a positive effect on process innovation performance, regardless of the innovation acceleration and hindrance factors. Unlike prior studies limited to technological innovation, this study analyzed the attitudes of enterprises toward innovation acceleration and hindrance factors. This study is expected to contribute to establishing a strategy for reducing the failure and risk of innovation due to its findings on how innovation performance varies by groups.

• 교육공학연구
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• v.33 no.4
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• pp.1001-1024
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• 2017

Flipped classroom has used widely in university in that its unique structure can facilitate learners' higher-thinking skills and promote competencies. Learners are expected to extend knowledge through performing online and offline, but they have difficulty in understanding their roles and specific behaviors to achieve the learning goals in the flipped learning. Therefore, a guidance for students has been required to support learners' mastery learning. The purpose of this study is to identify successful learners' characteristics in terms of "competency". For this, three-phased competency modeling was employed. In Phase I, Behavioral Event Interviews were conducted with eight learners of the flipped classroom. In Phase II for identifying competencies and developing a competency model, the data was coded, followed by testing reliability of the coding. Based on the meaning codes, competencies and behavioral indexes were developed. The final competencies consist of learning orientation, learning management, feedback seeking, peer interaction, and knowledge extension. In Phase III, validation of the competency model was conducted by explanatory factor analysis. As last, competencies were aligned by the two-phase of the flipped classroom. The finding will be used as the guidance for the learners and instructors in the flipped classroom.

• Journal of the Korea Society for Simulation
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• v.28 no.2
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• pp.35-48
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• 2019

Domestic hydraulic drifters till now have been developed by benchmarking products from overseas leading companies. However, they do not have excellent impact performance as they are not suitable for characteristics (large flow rate and low pressure) of Korean hydraulic drill power pack, and therefore, research on the optimum design has not made much headway. This study performs multi-objective function optimization for hydraulic drifters whose capacity has been redesigned to deal with the large flow rate, and also with the help of this function, it aims to improve impact power and reduce supply and surge pressure. A summary of the research study is as follows: First, we set goals for improving impact power, supply pressure, and surge pressure, and then perform multi-objective function optimization on them. After that, we secure the reliability of the optimized analytical model by comparing the test results of the prototype built by the optimized design with the analysis results of the analytical model. This study used SimulationX, that is the hydraulic system analysis software, and EasyDesign, which is a multi-objective function optimization program. Through this research, we have achieved the results that satisfy the goal of developing high power drifters suitable for Korean type hydraulic drills.

• Journal of the Korean GEO-environmental Society
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• v.20 no.2
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• pp.69-79
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• 2019

The coastal area forms various sedimentary layers according to the environmental conditions such as the topography and geological features of the upper region of the river, ocean currents, and river mouth. Therefore, identifying the characteristics of the marine clay deposited in the coastal area plays a key role in the investigation of the formation of soft ground. In general, alluvial grounds are formed by a variety of factors such as changes in topography and natural environment, they have very diverse qualities depending on the deposited region or sedimentation conditions. The most important thing for the construction of social infrastructures in soft ground areas is economical and efficient treatment of soft ground. In this study, the author collected data from diverse laboratory and field tests on five areas in western and southern offshore with relatively high reliability, and then statistically analyzed them, thereby presenting standard constants for construction design. Correlation between design parameters such as over consolidation ratio, preconsolidation pressure was analyzed using linear and non-linear regression analyses. Also, proposed distribution characteristics of design parameters in consideration of each region's uncertainty through statistical analyses such as normality verification, outlier removal.

• International Area Studies Review
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• v.14 no.1
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• pp.221-254
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• 2010

This study is for analyzing the mgmt performances of Korean tourism firms, operating as preparing strategically against FTA, one of the most importantly external environment in int'l mgmt since in the mid of 1990s. The main purpose can be mentioned to test empirically some relations between the mgmt performances of Korean tourism ones and the economic effects originated from FTA. The dependent variables of mgmt performances are classified with sales, profits and mgmt satisfaction, while the independent one regarding with economic effects from FTA are sorted based on the previous studies with the 2 following factors like direct with inbound/outbound and indirect effects. This study is conducted in two stages. Firstly, the research model is designed by the reviewing relevant theories and previous studies. Secondly, the survey of Korean tourism firms engaging in mgmt activities is implemented by collecting questionnaires. And for testing the hypothesis, the analyzing tools are used for correlation, reliability, validity and multi-regression on SPSS 12.0 and the path analysis of structural equation modeling is activated with AMOS 11.0.

• Journal of the Korean Society of Radiology
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• v.12 no.6
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• pp.785-791
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• 2018

Recently, Disk array is widely used as a long term storage device in PACS, but reliability is not enough in relation to annual failure rate of disk. Between October 2016 and February 2017, we scanned the serial port of the hard disk while reading or storing medical images on a PACS reader. The data rate was calculated from the data stored in HDD 99ea that were used in the PCAS image storage device and in HDD 101ea that were used in the Personal Computer. When a CT image was read from a PACS reader, Reading was 87.8% and Writing was 12.2% in units of several tens of megabytes or less. When the CT image was stored in the PACS reader, Reading was 11.4% and Writing was 88.6% in units of several tens of megabytes or less. While reading the excel file on the personal computer, Reading was 75% and Writing was 25% in less than 3 MB, and In the process of storing the excel file on the personal computer, Reading was carried out by 38% and Writing was carreid out 62% in the units of 3 MB or less. The transfer rate of the hard disk used in the PACS image storage device was 10 GB/h, and the transfer rate per hour of the hard disk of the personal computer was 5 GB / h. Annual failure rate of hard disk of image storage system is 0.97 ~ 1.13%, Annual failure rate of Hard Disk of personal computer is 0.97 ~ 1.13%. the higher transfer rate is, the higher annual failure rate is. These results will be used as a basis for predicting the life expectancy of the hard disk and the annual failure rate.