• Smart Structures and Systems
• /
• 제30권6호
• /
• pp.571-582
• /
• 2022

Optimal life-cycle management is a challenging issue for deteriorating regional bridges. Due to the complexity of regional bridge structural conditions and a large number of inspection and maintenance actions, decision-makers generally choose traditional passive management strategies. They are less efficiency and cost-effectiveness. This paper suggests a deep reinforcement learning framework employing double-deep Q-networks (DDQNs) to improve the life-cycle management of deteriorating regional bridges to tackle these problems. It could produce optimal maintenance plans considering restrictions to maximize maintenance cost-effectiveness to the greatest extent possible. DDQNs method could handle the problem of the overestimation of Q-values in the Nature DQNs. This study also identifies regional bridge deterioration characteristics and the consequence of scheduled maintenance from years of inspection data. To validate the proposed method, a case study containing hundreds of bridges is used to develop optimal life-cycle management strategies. The optimization solutions recommend fewer replacement actions and prefer preventative repair actions when bridges are damaged or are expected to be damaged. By employing the optimal life-cycle regional maintenance strategies, the conditions of bridges can be controlled to a good level. Compared to the nature DQNs, DDQNs offer an optimized scheme containing fewer low-condition bridges and a more costeffective life-cycle management plan.

• 정보처리학회논문지:소프트웨어 및 데이터공학
• /
• 제2권4호
• /
• pp.291-302
• /
• 2013

사이니지란 공공장소에서 불특정 다수의 이용자에게 특정 정보를 제공해 주는 미디어 기기이다. 최근에 상황인지 기술이 적용되면서 사이니지는 개인별 맞춤형 정보서비스를 제공할 수 있게 됨에 따라 단순한 광고 플랫폼에서 새로운 차원의 미디어 기기로 진화하고 있다. 본 연구의 목적은 사이니지에 대한 이용자들의 인식과 태도를 파악하고, 그것들을 유형별로 분류하여 사이니지 인식에 대한 기준을 제시하는 것이다. 본 연구에서는 사이니지에 대한 이용자의 인식과 태도를 파악하기 위해 관련 전문가와 실무자 인터뷰를 실시한 후, Q방법론을 활용하여 사이니지에 대한 이용자 인식과 태도를 유형별로 분류하였다. 본 연구 결과, 제1유형을 '스마트미디어 사이니지 인지형', 제2유형을 '수동형미디어 사이니지 인지형', 제3유형을 '양방향미디어 사이니지 인지형'이라고 각각 분류하여 분석하였다. 본 연구 결과는 향후 사이니지 관련 학술연구와 R&D에 유용한 가이드라인이 될 것이다.

• 커뮤니케이션디자인학연구
• /
• 제38권
• /
• pp.312-320
• /
• 2012

본 연구는 아이폰을 선호하는 사용자의 감성경험디자인 요소의 주관적 관점을 밝히는데 초점을 두었으며 주관성 연구를 위해 Q 방법론을 통해 4개의 유형을 발견할 수 있었다. 제 1 유형은 사용편의성 추구 유형으로 아이폰에 대한 충분한 사용적 이해가 있는 개인의 사용행태에 따른 기능, 이해의 용이성, 물리적 느낌, 사용성 모두를 중요하게 생각하는 사람들로 구성되어 있음을 알 수 있었다. 제 2 유형은 심미성 추구 유형으로 제품의 시각적인 정보에 의한 직관적이고 주관적인 심미적 인상을 중요하시는 유형을 구분되었다. 제 3 유형은 차별적 감성 추구 유형으로 자기 이미지나 자기가 소유한 제품을 통해 다른 이에게 전달하고자 하는 메시지를 중요하게 여기는 유형이며 제 4 유형은 아이폰에 대한 적극적이며 절대적인 선호도를 가지고 있는 유형으로 파악되었다.

• 한국IT서비스학회지
• /
• 제22권3호
• /
• pp.141-165
• /
• 2023

With the advent of the fourth industrial revolution, technologies such as the Internet of Things, artificial intelligence and cloud computing are developing rapidly, and smart homes enabled by these technologies are rapidly gaining popularity. To gain a competitive advantage in the global market, companies must understand the differences in consumer needs in different countries and cultures and develop corresponding business strategies. Therefore, this study conducts a comparative analysis of consumer reviews of smart homes in South Korea and China. This study collected online reviews of SmartThings, ThinQ, Msmarthom, and MiHome, the four most commonly used smart home apps in Korea and China. The collected review data is divided into satisfied reviews and dissatisfied reviews according to the ratings, and topics are extracted for each review dataset using LDA topic modeling. Next, the extracted topics are classified according to five evaluation factors of Perceived Usefulness, Reachability, Interoperability,Trustness, and Product Brand proposed by previous studies. Then, by comparing the importance of each evaluation factor in the two datasets of satisfaction and dissatisfaction, we find out the factors that affect consumer satisfaction and dissatisfaction, and compare the differences between users in Korea and China. We found Trustness and Reachability are very important factors. Finally, through language network analysis, the relationship between dissatisfied factors is analyzed from a more microscopic level, and improvement plans are proposed to the companies according to the analysis results.

• Structural Engineering and Mechanics
• /
• 제23권1호
• /
• pp.97-113
• /
• 2006

A simply supported hybrid plate consisting of top and bottom functionally graded elastic layers and an intermediate actuating or sensing homogeneous piezoelectric layer is investigated by an elasticity (piezoelasticity) method, which is based on state space formulations. The general spring layer model is adopted to consider the effect of bonding adhesives between the piezoelectric layer and the two functionally graded ones. The two functionally graded layers are inhomogeneous along the thickness direction, which are approached by laminate models. The effect of interlaminar bonding imperfections on the static bending and free vibration of the smart plate is discussed in the numerical examples.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
• /
• pp.303-306
• /
• 2006

A roll rate estimation method is proposed using the GPS measurement for spinning vehicles such as guided munitions and smart bombs. Before designing the roll rate estimator, the carrier phase and the carrier frequency deviation caused by spinning have been observed. Based on the observation, the spinning frequency is estimated using I and Q value from the correlator. The proposed method is evaluated through computer simulations using a software defined receiver and a GPS IF signal generator.

• 스마트미디어저널
• /
• 제9권4호
• /
• pp.36-43
• /
• 2020

The Monte Carlo tree search (MCTS) is a popular method for implementing an intelligent game program. It has several hyper-parameters that require an optimization for showing the best performance. Due to the stochastic nature of the MCTS, the hyper-parameter optimization is difficult to solve. This paper uses the self-playing capability of the MCTS-based game program for optimizing the hyper-parameters. It seeks a winner path over the hyper-parameter space while performing the self-play. The top-q longest winners in the winner path compete for the final winner. The experiment using the 15-15-5 game (Omok in Korean name) showed a promising result.

• Structural Engineering and Mechanics
• /
• 제34권4호
• /
• pp.449-474
• /
• 2010

A smart hollow cylinder consisting of a host functionally graded elastic core layer and two surface homogeneous piezoelectric layers is presented in this paper. The bonding between the layers can be perfect or imperfect, depending on the parameters taken in the general linear spring-layer interface model. The effect of such weak interfaces on free vibration and steady-state response is then investigated. Piezoelectric layers at inner and outer surfaces are polarized axially or radially and act as a sensor and an actuator respectively. For a simply supported condition, the state equations with non-constant coefficients are obtained directly from the formulations of elasticity/piezoelasticity. An approximate laminated model is then introduced for the sake of solving the state equations conveniently. It is further assumed that the hollow cylinder is embedded in an elastic medium and is simultaneously filled with compressible fluid. The interaction between the structure and its surrounding media is taken into account. Numerical examples are finally given with discussions on the effect of some related parameters.

• 조명전기설비학회논문지
• /
• 제23권7호
• /
• pp.57-66
• /
• 2009

Microturbines system (MTS) are currently being deployed as small scale on-site distributed generators for microgrids and smart grids. In order to fully exploit DG potentialities, advanced integrated controls that include power electronics facilities, communication technologies and advanced modeling are required. Significant expectations are posed on gas microturbines that can be easily installed in large commercial and public buildings. Modeling, control, simulation of microturbine generator based distributed generation system in smart grid application of buildings for both grid-connected and islanding conditions are presented. It also incorporates modeling and simulation of MT with a speed control system of the MT-permanent magnet synchronous generator to keep the speed constant with load variation. Model and simulations are performed using MATLAB, Simulink and SimPowerSystem software package. The model is built from the dynamics of each part with their interconnections. This simplified model is a useful tool for studying the various operational aspects of MT and is also applicable with building cooling, heating and power (BCHP) systems

• 한국환경생태학회지
• /
• 제36권6호
• /
• pp.662-675
• /
• 2022

본 연구는 보길도 격자봉과 큰길재를 잇는 능선부를 중심으로 분포하는 회양목 생육지역의 체계적인 보전 및 관리를 위한 기초자료를 제공하고자 식물군집구조 현황을 조사·분석하였다. 조사구는 관목층에 분포하는 회양목의 밀도와 지형, 향 등 입지적인 특성을 고려하여 대표적인 식생 군락 또는 지형의 변화가 있는 지역을 대상으로 총 26개소를 설정하였다. DCA와 TWINSPAN에 의해 소사나무-낙엽활엽수군락, 소사나무군락, 소사나무-회양목군락, 소사나무-상록활엽수군락, 붉가시나무군락, 황칠나무-붉가시나무군락으로 분류되었다. 소사나무가 우점하는 군락은 당분간 현상태를 유지할 것이나 장기적으로는 주변에 붉가시나무가 우점하고 있어 이들 종으로의 천이잠재성이 높았다. 붉가시나무군락, 황칠나무-붉가시나무군락의 경우 난대림의 극상 수종으로 알려진 붉가시나무가 우점하는 현상태를 유지할 것이다. 회양목의 경우에도 소사나무가 우점하는 군락은 지형적인 조건으로 인해 양호한 상태를 유지하겠으나 붉가시나무 우점 군락의 경우, 피도가 높은 특성으로 인해 생육상 어려움이 예상된다. 환경요인과 식생분포간의 관계에서는 토양산도(pH)만 식생분포에 영향을 미친 것으로 분석되었다. 그 외에 pH는 3.78~5.30, 전기전도도는 0.186~0.543dS/m, 유기물함량은 2.25~2.89%로 전반적으로 낮았다.