• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.3
• /
• pp.75-81
• /
• 2012

With the advance of internet technology and fast growing of data volume, it become very hard to find a demanding information from the huge amount of data. Recommender system can solve the delema by helping a user to find required information. This paper proposes a reinforcement learning based hybrid recommendation system to predict user's preference. The hybrid recommendation system combines the content based filtering and collaborate filtering, and the system was tested using 2000 images. We used mean abstract error(MAE) to compare the performance of the collaborative filtering, the content based filtering, the naive hybrid filtering, and the reinforcement learning algorithm based hybrid filtering methods. The experiment result shows that the performance of the proposed hybrid filtering performance based on reinforcement learning is superior to other methods.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.12 no.4
• /
• pp.11-17
• /
• 2008

This study evaluates the seismic performance of post-tensioned flat plate structures with or without slab bottom reinforcement. For this purpose, 3 and 9 story frames were designed only considering gravity loads. This study conducts a nonlinear static pushover analysis. This study was an analytical model that is able to represent punching shear failure and fracture mechanism. The analytical results showed that the seismic performance of a post-tension flat plate is strongly influenced by the existence of slab bottom reinforcement through column. By placing slab bottom reinforcement in a PT flat plate frame, lateral strength and max drift capacity are significantly increased.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.13 no.2
• /
• pp.171-179
• /
• 2013

Recognition and image processing technology depends on illumination variation. One of the most important factors is the parameters of algorithms. When it comes to select these values, the system has different types of recognition accuracy. In this paper, we propose performance improvement of the eye tracking system that depends on some environments such as, people, location, and illumination. Optimized threshold parameter was decided by using reinforcement learning. When the system accuracy goes down, reinforcement learning used to train the value of parameters. According to the experimental results, the performance of eye tracking system can be improved from 3% to 14% by using reinforcement learning. The improved eye tracking system can be effectively used for human-computer interaction.

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.1486-1491
• /
• 2010

Recently, the frequency and magnitude of the earthquake have increased. The structural safety of the public facilities such as bridges and tunnels etc. which were not concerned for earthquake resistant design are increased. Fiber reinforcement polymer that has been frequently studied for seismic retrofit has advantage as seismic reinforcement material, but it has disadvantage of the brittleness. Therefore, the investigation of safety and seismic reinforcement are required. In this study, new FRP-ductile material layered composites proposed to seismic performance reinforced of subway tunnel. Tensile test of FRP-ductile material layered composites showed that Maximum tensile force of FRP-ductile using Aluminum is similar to existing FRP reinforcement material and maximum strain was increased. In case of application of domestic subway tunnel which need ductility, layered composites of FRP-Aluminum is estimated effectively for increase of seismic performance.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.18 no.6
• /
• pp.97-104
• /
• 2014

Hollow slab is a floor system which reduces the load of vertical structural members and earthquake load by decreasing self-weight of slab. Although hollow slab can reduce self-weight of slab remarkably, flexural strength and shear strength reduce due to the hollow section inside the slab, so it is very important to predict structural behavior. In spite of plenty of domestic and foreign studies on hollow slab, there is a shortage of research on shear performance according to shear reinforcement of one-way hollow slab. Therefore, this study aims to verify the need for shear reinforcement of one-way hollow slab by analyzing failure modes of one-way hollow slab depending on the state of shear reinforcement and comparing shear strengths of estimation formula and experimental value with one another.

• Journal of the Architectural Institute of Korea Structure & Construction
• /
• v.36 no.2
• /
• pp.137-144
• /
• 2020

The purpose of this study is to experimentally evaluate the effect of improving seismic performance by applying the details of seismic reinforcement to the reinforced concrete frame with non-seismic details while maintaining the original opening shape. In this study, based on CF specimens with specific seismic details, a total of four full scale specimens were designed and fabricated. The main variables are the width and spacing of steel dampers installed in the upper and lower parts of seismic reinforcement details, and the presence or absence of torsion springs installed in the hinges. As a result of the test, it was evaluated to be helpful for seismic retrofit and opening isolation of steel dampers installed at the upper and lower parts of the seismic reinforcement details and torsion springs installed at the joints. In particular, CFR2S specimens with torsion springs showed the best performance in terms of strength, stiffness and energy dissipation capacity with increasing displacement angle.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.24 no.1
• /
• pp.123-132
• /
• 2021

In order for the underwater vehicle to perform various tasks, it is important to control the depth, course, and roll of the underwater vehicle. To design such a controller, it is necessary to construct a dynamic model of the underwater vehicle and select the appropriate hydrodynamic coefficients. For the controller design, since the dynamic model is linearized assuming a limited operating range, the control performance in the steady state is well satisfied, but the control performance in the transient state may be unstable. In this paper, in order to overcome the problems of the existing controller design, we propose a A2C(Advantage Actor-Critic) based roll controller for underwater vehicle with stable learning performance in a continuous space among reinforcement learning methods that can be learned through rewards for actions. The performance of the proposed A2C based roll controller is verified through simulation and compared with PID and Dueling DDQN based roll controllers.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.24 no.6
• /
• pp.138-145
• /
• 2020

This study was conducted to identify the structural performance of the opening in a location close to the support point in the perforated beam system of steel beams. In addition, structural performance was determined through experiments on reinforced openings using vertical and horizontal steel plates. In the steel simple beam, it was found that the opening was in a position closer to the support point, half the height of the steel beam (D/2), which was more appropriate than the height of the steel beam (D). In addition, the reinforcement effect of horizontal steel plate was greater than that of vertical steel plate reinforcement. Structural performance was improved when there was no gap between openings and steel plates.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.03a
• /
• pp.697-703
• /
• 2008

Excessive water leakage phenomenon happens through damage of nation core zone of about 17,000 storage of water facilities or collapse of dam is worried, is being damaged or enforce dilapidated fill dam core zone's repair reinforcement. Example that use grouting method of construction considering construction and economic performance etc. recently by repair reinforcement way about defect of dam is increased. Permeation grouting method repair & reinforcement of fill dam countermeasure is preferred in nation. Do that is economical to decide these repair reinforcement effect and grouting effect estimation method that do not give damage to dam is effective. Therefore, observing electricity resistivity Survey change of dam since grouting reinforcement using Electric resistivity Survey inquiry of seismic survey method in this research, Wished to verify grouting effect whether is possible as Electric resistivity Survey, and study whether integrity of dam through repair reinforcement defined.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.16 no.6
• /
• pp.1-8
• /
• 2012

This study estimates the performance of confined concrete according to the configuration of transverse steel bars. The main test variables were the yield strength of spiral reinforcement and configuration of transverse reinforcement. A total of 27 specimens with rectangular cross section were cast and tested under monotonic concentric compression. R-type specimens with rectangular spirals, C-type specimens with circular spirals and O-type specimens with combined shape of rectangular and octagon were designed in this study. From experimental results, it is concluded that the proposed configuration of transverse reinforcement can provided improved ductility to the confined concrete compared to rectangular spiral reinforcement.