• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.2
• /
• pp.200-209
• /
• 2019

When forecasting future values, a model estimated after minimizing training errors can yield test errors higher than the training errors. This result is the over-fitting problem caused by an increase in model complexity when the model is focused only on a given dataset. Some regularization and resampling methods have been introduced to reduce test errors by alleviating this problem but have been designed for use with only a given dataset. In this paper, we propose a new optimization approach to reduce test errors by transforming a test error minimization problem into a training error minimization problem. To carry out this transformation, we needed additional data for the given dataset, termed pseudo data. To make proper use of pseudo data, we used three types of missing data imputation techniques. As an optimization tool, we chose the least squares method and combined it with an extra pseudo data instance. Furthermore, we present the numerical results supporting our proposed approach, which resulted in less test errors than the ordinary least squares method.

• Journal of the Korea Convergence Society
• /
• v.10 no.8
• /
• pp.115-120
• /
• 2019

This study aims to prove the value of convergence-based mobile English curriculum for English education prior to its practical use. This is deferent from the existing studies in developing and studying a curriculum using an English program loaded in mobile to make an effective English learning. In order to find out how well teachers are aware of this curriculum, we performed qualitative researches. Some English teachers asked for feedback about the curriculum gave us positive feedback in most areas such as learning authentic English, repetition effects, cooperative learning, self-efficacy experience, and so on. As a negative feedback, they were afraid of students' easy and free attitudes because of the new learning environments. This problem can be solved by the very close communications between teacher and student through on and off line. Next time applying this curriculum to the field and analyzing will be expected.

• Journal of Convergence for Information Technology
• /
• v.9 no.9
• /
• pp.210-218
• /
• 2019

The purpose of this study was to establish the basic data of rational work environment management by grasping the interrelationship between motivation or organizational fairness and retention intention. From March 1, 2019 to April 12, 2019, clinical dental hygienists working in dental hospitals and clinics in Seoul, Gyeonggi, Chungcheong, and Jeonra provinces were sampled as a convenience, using self-informative methods. There was a significant positive correlation between motivation and organizational fairness, and there was a positive correlation with retention intention. Organizational fairness had a positive correlation with retention intention. Therefore, it is necessary to increase the efficiency of the dental hygienists by establishing the working period based on the positive organizational fairness and the application of the active motivation program to increase the dental hygienist's intention.

• The Korean Journal of Archival Studies
• /
• no.52
• /
• pp.171-212
• /
• 2017

Music has been created and played in various environments over a long time, with each piece having distinct sentiments and stories. Different people can have varying interpretations of one song depending on their viewpoints shaped by personal experiences and attitudes. In fact, the audience's understanding may differ greatly from the songwriter's intended message. Knowing this, music can serve as a reflection of one's contemporary sentiment. In the works of art such as music, the creator's intention becomes the background of the work or, sometimes, the main meaning. However, given that popular music is often under the control of companies and distributors and influenced by "capital," creators are required to adjust to mainstream preferences and, therefore, cannot fully express themselves in their music. On the other hand, indie music allows creators to pursue their own music given its "independence" from capital. With this, this study aims to collect and analyze data on the activities that Korean indie bands carry out, and examine their meaning and significance in society.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.19 no.1
• /
• pp.85-95
• /
• 2019

This work shows how to design a robot structure and to control to overcome obstacles while traveling through ducts of various diameters and shapes by three-legged robot. Circuits are centered in the body to connect the three wheel bodies that are driven around the center body with the 4-section slider link structure. Also, the springs are used to contract and expand the robot legs so that it can be caparable of various environments. Geared motor, spring, and belt were selected based on the static and dynamic calculation to be suitable to horizontal and vertical travels. The center body is equipped with a camera and the distance sensors, and a control algorithms are implemented so that it can be successfully performed in L-type and T-type ducts. Using UWB modules and trilateration algorithm, the location of the duct-cleaning robot inside the duct could be identified successfully.

• Journal of Digital Convergence
• /
• v.17 no.1
• /
• pp.141-148
• /
• 2019

The advancement of digital technology accelerates intelligence, convergence, and demands better change beyond traditional methods in all aspects of business models and technologies, infrastructure, processes, and platforms. Risk management is becoming more important because of various security risks, depending on the changing business environment and aligned to business goals is emerging from the existing information asset based risk management. For business aligned risk management, it is essential to understand the risk appetite for achieving business goals, which provides a basis for decision-making in subsequent risk management processes. In this paper, we propose a framework for analyzing the risk management framework, pre - existing risk analysis, and protection motivation theory that influences decisions on security risk management. To examine the practical feasibility of the developed risk appetite framework, we reviewed the applicability and significance of the proposed risk appetite framework through an advisory committee composed of security risk management specialists.

• Journal of Digital Convergence
• /
• v.17 no.1
• /
• pp.457-465
• /
• 2019

This study was designed to develop a positive behavior support model for children in child care institutions. For this purpose, a demand survey for PBS was conducted with 55 child care institution staff members. 76% of the respondents responded that PBS is needed to prevent problem behavior and can be a good alternative for personality education, and approximately 70% responded that they are willing to implement PBS. The specifications of the model are suggested as follows. First, the preparation step would consist of establishing a support team, educating staff members about PBS, selecting expected behaviors, assessing the current baseline behavior, and setting up a universal PBS environment. The application step would consist of instructing social skills, implementing reinforcement, personal goal-setting and assessing behavior, educating trouble-making students, and monitoring. Finally, at the outcome assessment period, measuring the change in target behavior from the pre-intervention to the post-intervention stage, change in social skills and academic achievement, and social validity is suggested. It is expected that application of this model to children in child care institution will decrease problem behaviors of students, enhance desirable behaviors, and boost the staff members' efficacy.

• Journal of the Korea Convergence Society
• /
• v.10 no.4
• /
• pp.91-97
• /
• 2019

The aim of this study was to compare effects of oral health education on oral health behavior according to demographic and dental health-related characteristics in inpatient alcoholics. 62 alcoholic male patients were recruited to 32 patients at education group and 30 at non-education group. To search demographic and dental health-related characteristics, the self-administered structured questionnaires were used, and the survey was conducted before and after the oral health education. The oral health education program was consisted of 40 mins theoretical education and individual tooth brushing training once a week for 4 weeks. The oral health education for alcoholic patients had big effects on oral health behavior. And these results indicate that if oral health program was performed systematically in alcohol counseling centers or alcohol hospitals, more oral health promotion effects will appear.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.23 no.3
• /
• pp.159-167
• /
• 2019

2016 Gyeongju and 2017 Pohang earthquakes led Koreans to acknowledge that the Korean peninsula is not an earthquake-free zone anymore. Among various buildings crucial to after-shock recovery, general hospital buildings, especially existing old ones, are very significant so seismic retrofitting of those must be an important issue. Self-centering energy dissipative(SCED) brace is one of retrofitting methods, which consists of tendon with restoring force and friction device capable of dissipating seismic energy. The strength of the SCED brace is that the tendon forces a structure to go back to the original position, which means residual drift can be negligible. The residual drift is a very important parameter to determine usableness of general hospitals after shock. To the contrary, buckling-restrained braces(BRB) are also a very effective way to retrofit because they can resist both compressive and tensile, but residual drift may exist when the steel core yields. On this background, the seismic retrofitting effect of general hospitals reinforced with SCED braces was investigated and compared to that of the BRD in this study. As a result, although the floor acceleration cannot be reduced, the story drift and residual drift, and the shear demand of walls significantly decreased. Consequently, seismic retrofitting by SCED braces are very effective for domestic low-rise general hospitals.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.271-271
• /
• 2019

하천에서의 식생은 하천의 조도 및 흐름특성을 변화시키는 요인 중 하나로서 하천 내의 식생밀도 변화로 인하여 발생한 하상변동은 장기적으로 하천내의 하중도가 발생하거나, 식생으로 인해한 방향으로 편중된 흐름으로 인하여 제내지 방향으로의 하천 침식이 발생하고, 이에 따라 구조물의 안정성에 영향을 미치는 등 하천의 중 장기 계획 시 고려해야할 중요한 요인이다. 이에 따라 식생 모형을 이용한 다양한 흐름특성 분석 실험들이 수행되었으나, 대부분의 연구에서는 식생을 단순화하여 모형으로 사용하였기 때문에 실제 식생에 대한 영향성을 보기에는 한계가 존재한다. 건설기술연구원의 하천실증연구센터에서는 이러한 식생의 영향을 분석하기 위하여 네덜란드의 Deltares, 핀란드의 Aalto 대학 등과 함께 다년간 국제공동연구를 수행하였으며, 금번 소개하는 실험에서는 식생밀도에 따른 흐름변화, 하상변동 및 환경 변화 등의 검토를 목적으로 하였다. 실험은 총 2가지 유량 조건에 대하여 수행되었으며, 실험 중 흐름의 안정화를 확인하기 위하여, 유출수조에는 6개의 압력식 수위계를 설치하여 실험기간동안 유출수조에서의 수심변화를 측정하였고, 하도에는 실험구간 상 하류에 SonTek의 SL-1500 및 SL-3000을 이용하여 지속적으로 수심을 측정하고, 이 외에도 하류단에 2개의 압력식 수위 측정장비를 설치하여 수심을 모니터링하였다. 실험에 사용된 식생은 높이 약 1.5m의 2가지 밀도로 폭 2m, 길이 4m의 규모로 설치하였고, 광파기와 3차원 레이저 스캐너를 이용하여 실험 전 후의 식생 주변 및 전 실험구간의 하상을 측량하였다. 흐름특성 분석을 위한 수리 측정은 Nortek사의 Vectrino를 이용하여 측정하였고, 총 24개 측선에 대하여 각 측선별 5 ~ 10개의 유속자료를 측정하였으며, 각 측점별로 90초간 자료를 수집하였다. 흐름특성 분석에 사용된 유속자료는 이상치를 제거한 후 수행되었으며, 이상치의 제거는 표준편차의 3배 이상의 편차를 갖거나, 측정자료의 자기상관도가 70% 이하인 값들은 제거한 후 분석을 수행하였다. 흐름 분석을 위한 측정자료를 이 외에도 캠코더를 이용한 표면유속영상 측정기법과 ADCP를 이용한 측정도 병행하였으나, 본 연구에서는 Vectrino로 측정된 결과만을 소개하고자 한다.