• Smart Structures and Systems
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• 제9권1호
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• pp.1-20
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• 2012

In bridge engineering, maintenance strategies and thus budgetary demands are highly influenced by construction type and quality of design. Nowadays bridge owners and planners tend to include life-cycle cost analyses in their decision processes regarding the overall design trying to optimize structural reliability and durability within financial constraints. Smart permanent and short term monitoring can reduce the associated risk of new design concepts by observing the performance of structural components during prescribed time periods. The objectives of this paper are the discussion and analysis of influence line or influence field approaches in terms of (a) an efficient incorporation of monitoring information in the structural performance assessment, (b) an efficient characterization of performance indicators for the assessment of structures, (c) the ability of optimizing the positions of sensors of a monitoring system, and (d) the ability of checking the robustness of the monitoring systems applied to a structure. The proposed influence line- model correction approach has been applied to an integrative monitoring system that has been installed for the performance assessment of an existing three-span jointless bridge.

• 상하수도학회지
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• 제28권1호
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• pp.1-11
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• 2014

The water distribution system should be invariably operated on continuous pattern for 24 hours a day. Occasionally, it is not practically possible to operate for 24 hours due to water shortage or financial constraints. Therefore an intermittent water supply is unavoidable in water shortage area and developing countries. But the intermittent water supply can introduce large pressure forces and rapid fluid accelerations into a water supply network. These disturbances may result in new pipe failure, leakage and secondary contamination. This paper proposed an improvement methodology to prevent the disturbances by intermittent water supply. For the study, the hydraulic variation of intermittent flow in water distribution system was measured and analyzed in the field by comparing with simulation of hydraulic model. Installations of control valves such as, pressure reducing and sustaining and air valves were employed for pressure and flow control. The effectiveness of the methods are presented by comparing hydraulic conditions before and after introducing the proposed solutions.

• 한국주거학회논문집
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• 제28권1호
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• pp.83-93
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• 2017

This research intends to find out the impact of housing wealth of home-owning pre-retirees and older adults consisting of young-old, middle-old and old-old groups on their household consumption. In doing so, this research analyzes 2,350 home-owning households by utilizing the 17th Korean Labour and Income Panel Study (KLIPS). The results show that housing wealth has a statistically significant effect on non-durable consumption of the pre-retirees, and young-old and middle-old groups of older adults, and housing wealth has a much stronger effect on household expenditure than does financial wealth or real estate. It's found that the consumption elasticity is particularly greater for female-headed households living in SMA, residing in apartments, holding a lower debt-to-asset ratio and being a pensioner. The empirical findings imply that the old-old group of older adults is unlikely to actively tap into their housing windfalls since housing asset becomes the last to dispose in the course of an individual's life. As housing wealth effects are especially strong when liquidity constraints faced by older adults are removed, it's of significance to substantially reduce household debt before retirement in order to constantly maintain an adequate level of household consumption or to promptly prepare for future contingencies.

• Management Science and Financial Engineering
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• 제14권1호
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• pp.23-34
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• 2008

In this study, we consider stationary waiting times in a Poisson driven single-server m-node queues in series. We assume that service times at nodes are independent, and are either deterministic or non-overlapped. Each node excluding the first node has a finite waiting line and every node is operated under a FIFO service discipline and a communication blocking policy (blocking before service). By applying (max, +)-algebra to a corresponding stochastic event graph, a special case of timed Petri nets, we derive the explicit expressions for stationary waiting times at all areas, which are functions of finite buffer capacities. These expressions allow us to compute the performance measures of interest such as mean, higher moments, or tail probability of waiting time. Moreover, as applications of these results, we introduce optimization problems which determine either the biggest arrival rate or the smallest buffer capacities satisfying probabilistic constraints on waiting times. These results can be also applied to bounds of waiting times in more general systems. Numerical examples are also provided.

• Safety and Health at Work
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• 제6권1호
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• pp.46-55
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• 2015

Background: Small and medium enterprises (SMEs) are often the main pillar of an economy. Minor accidents, ergonomics problems, old and outdated machinery, and lack of awareness have created a need for implementation of safety practices in SMEs. Implementation of healthy working conditions creates positive impacts on economic and social development. Methods: In this study, a questionnaire was developed and administered to 30 randomly chosen SMEs in and around Mumbai, Maharashtra, and other states in India to evaluate safety practices implemented in their facilities. The study also looked into the barriers and drivers for technology innovation and suggestions were also received from the respondent SMEs for best practices on safety issues. Results: In some SMEs, risks associated with safety issues were increased whereas risks were decreased in others. Safety management practices are inadequate in most SMEs. Market competitiveness, better efficiency, less risk, and stringent laws were found to be most significant drivers; and financial constraints, lack of awareness, resistance to change, and lack of training for employees were found to be main barriers. Conclusion: Competition between SMEs was found to be major reason for implementation of safety practices in the SMEs. The major contribution of the study has been awareness building on safety issues in the SMEs that participated in the project.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2014년도 추계학술대회
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• pp.167-168
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• 2014

연안여객선은 도서민의 감소로 인한 경영수지악화로 신규선 투입과 운항 횟수 증가와 같은 서비스 개선을 기대하기 어렵다. 또한 안전관리의 미흡과 낮은 임금 및 근로 환경의 문제로 우수 선원의 수급이 어려워 선박 운항의 안전성 또한 문제가 되고 있다. 공공성과 안전성 확보를 위해 공영제를 도입한 운영체계 개선이 필요하다. 여러 현실적 제약이 있지만 보조항로부터 시행하면서 안전관리 강화 등을 통해 부실한 업체의 면허를 회수해 공영항로를 확보해 간다면 공영제를 통한 운영체계 개선이 가능할 것이다.

• 산업경영시스템학회지
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• 제36권3호
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• pp.8-16
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• 2013

Determining relative importance among many quality attributes under financial constraints is an important task. The weighted value of an attribute particularly in QFD, will influence on engineering characteristics and this will eventually influence the whole manufacturing process such as parts deployment, process planning, and production planning. Several scholars have suggested weighting formulas using CSC (Customer Satisfaction Coefficient) in the Kano model. However, previous research shows that the validity of the CSC approaches has not been proved systematically. The aim of the present study is to address drawbacks of CSC and to develop APC (Average Potential Coefficient), a new approach for weighting of quality attributes. For this, the current study investigated 33 quality attributes of e-learning and conducted a survey of 375 university students for the results of APC, the Kano model, and the direct importance of the quality attributes. The results show that the proposed APC is better than other approaches based on the correlation analysis with the results of direct importance. An analysis of e-leaning's quality perceptions using the Kano model and suggestions for improving e-learning's service quality are also included in this study.

• 한국산업융합학회 논문집
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• 제22권6호
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• pp.637-647
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• 2019

In this study, we analyzed seismic behavior of reinforced earth retaining wall through the model test in order to characterize the behavior of reinforced earth retaining wall during earthquake. A scale model test was performed based on similitude ratio in accordance with law of similitude due to time and financial constraints on real scale modeling experiments. Seismic resistance characteristics of each seismic waves were analyzed by assessing the variations measured through excitation of the excited acceleration of 0.05g, 0.1g, 0.15g, and 0.2g. The results of this study, it would be important to obtain reasonable and abundant data on ground properties and seismic design in preparation for earthquakes when assessing the safety of block type reinforced earth retaining wall confined to model experiment. Acquisition of those data and systematic analytical techniques are considered likely to have a significant effect on the decrease of structure damage caused by earthquakes in Korea which has recently witnessed frequent occurrence of earthquakes.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제8권1호
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• pp.9-16
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• 2019

스마트폰은 휴대용 컴퓨터로서 자리매김하고 있다. 이에 따라 가장 민감한 금융 응용 서비스조차 스마트폰을 통해 언제 어디서나 사용할 수 있게 되었다. 스마트폰은 일반 PC에 비해 무선인터넷, 이동통신망을 비롯하여 블루투스, NFC 등 근거리 통신망 등 다양한 경로를 통하여 외부와 통신하고 있으며 매우 다양한 앱이 제공되고 있어 취약점이 존재할 경우, 공격의 피해가 발생할 가능성이 높아진다. 본 논문에서는 여러 가지 물리적 제약점이 있는 스마트폰의 은행앱에서 로그인에 사용되는 동적 가상키보드의 취약점에 대하여 분석하고, 그 대응방안을 제시한다.

• International Journal of Advanced Culture Technology
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• 제11권3호
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• pp.302-309
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• 2023

This study aimed to develop a VR-based digital therapeutic intervention for the diagnosis and treatment of ADHD. The research combined medical data with virtual reality technology to develop an algorithm for ADHD diagnostic scales and implemented a VR-based digital therapeutic platform using a head-mounted display (HMD). This platform can be used for the diagnosis and treatment of ADHD in children and adolescents. Additionally, we four VR games were developed, including archery timing, Antarctic exploration, grocery shopping, and rhythm-based drumming(RBD), incorporating various psychiatric treatment techniques based on cognitive-behavioral therapy(CBT). To evaluate the usability of this digital therapeutic intervention, a group of experts specialized in counseling psychology participated in the study. The evaluations received highly positive feedback regarding the ability to access the system menu while wearing the HMD, the consistency of terminology used in menus and icons, the usage of actual size for 3D graphic elements, and the support for shortcut key functionality. The assessments also indicated that the games could improve attention, working memory, and impulse control, suggesting potential therapeutic effects for ADHD. This intervention could provide a daily treatment method for families experiencing financial constraints that limit hospital-based therapies, thereby reducing the burden.