• Smart Structures and Systems
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• v.13 no.3
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• pp.353-374
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• 2014

Recent studies were dedicated to the realization of measurements on stay-cable samples of different geometry and static conditions as available at several facilities. The elaboration of the acquired data showed a a satisfactory efficacy of the dampers made of NiTi wires in smoothing the cable oscillations. A further attempt to investigate the applicability of the achieved results beyond the specific case-studies represented by the tested cable-stayed samples is herein pursued. Comparative studies are carried out by varying the diameter of the NiTi wire so that similar measurements can be taken also from laboratory steel cables of reduced size. Details of the preparation of the Ni-Ti wires are discussed with particular attention being paid to the suppression of the creep phenomenon. The resulting shape of the hysteretic cycle differs according to the wire diameter, which affects the order of the fitting polynomial to be used when trying to retrieve the experimental results by numerical analyses. For a NiTi wire of given diameter, an estimate of the amount of dissipated energy per cycle is given at low levels of maximum strain, which correspond to a fatigue fracture life of the order of millions of cycles. The dissipative capability is affected by both the temperature and the cycling frequency at which the tests are performed. Such effects are quantified and an ageing process is proposed in order to extend the working temperature range of the damper to cold weathers typical of the winter season in Northern Europe and Canada. A procedure for the simulation of the shape memory alloy behavior in lengthy cables by finite element analysis is eventually outlined.

• Smart Structures and Systems
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• v.16 no.2
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• pp.281-294
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• 2015

Bolted joint connection is the most commonly used connection element in structures and devices. The loosening due to external dynamic loads cannot be observed and measured easily and may cause catastrophic loss especially in an extreme requirement and/or environment. In this paper, an innovative Real-time Cross-Correlation Method (RCCM) for monitoring of the bolted joint loosening was proposed. We apply time reversal process on stress wave propagation to obtain correlation signal. The correlation signal's peak amplitude represents the cross-correlation between the loosening state and the baseline working state; therefore, it can detect the state of loosening. Since the bolt states are uncorrelated with noise, the peak amplitude will not be affected by noise and disturbance while it increases SNR level and increases the measured signals' reliability. The correlation process is carried out online through physical wave propagation without any other post offline complicated analyses and calculations. We implemented the proposed RCCM on a single bolt/nut joint experimental device to quantitatively detect the loosening states successfully. After that we implemented the proposed method on a real large structure (reaction wall) with multiple bolted joint connections. Loosening indexes were built for both experiments to indicate the loosening states. Finally, we demonstrated the proposed method's great anti-noise and/or disturbance ability. In the instrumentation, we simply mounted Lead Zirconium Titanate (PZT) patches on the device/structure surface without any modifications of the bolted connection. The low-cost PZTs used as actuators and sensors for active sensing are easily extended to a sensing network for large scale bolted joint network monitoring.

• Journal of Satellite, Information and Communications
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• v.11 no.4
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• pp.107-113
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• 2016

In this paper, we suggest a design method of a wide-band Butler matrix working at 5.9 GHz for V2X communication antennas. Since V2X communication needs beam-forming and beam-steering antennas to make transportation systems, mobile comm platforms, saturated frequency-resources, and signal TX-and-RX smart, multi-functional, resolved, and efficient utmost, respectively, the proper Butler matrix and its radiating elements as a low-profile geometry are realized. The constitutive components of the basic Butler matrix of a narrow band are designed first. And then, it is extended to a wide-band version to make its frequency-shift less affected by the event of the antenna system being mounted on a car body. The beam-forming and beam-steering performance is presented as the common feature tagged along with the different bandwidths of the frequency responses as the comparison between the narrow- and wide-band cases.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.726-734
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• 2019

The current maritime industry is expected to have a significant impact on the role of maritime-related technologies and systems, especially seafarers, in the rapidly changing Fourth Industrial Revolution. The Maritime Autonomous Surface Ship (MASS) aims to reduce the number of safety accidents and improve seafarers' working environment. With regard to MASS, the International Maritime Organization has been trying to minimize unexpected impact in the maritime education and training sector by establishing international conventions such as the Standards of Training, Certification and Watchkeeping for Seafarers. However, domestic designated educational institutions have not yet established an education and training scheme to develop seafarers who will be on board for MASS. Therefore, this paper reviews the technology of MASS, analyzes the changes in education and training in order to upgrade the qualifications, and suggests the competencies of smart seafarers equipped with the integrated management ability required for Artificial Intelligence, Big Data, Cybersecurity, and the Digital System Revolution through education and training. In addition, this study provides basic information for the education and training of seafarers who are optimized for the rapidly changing technological environment.

• Journal of the Korea Society of Computer and Information
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• v.21 no.10
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• pp.175-182
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• 2016

In the 21st century knowledge and information society, Electronic Contracts made with the intention of electronic computer information networks are emerging as a new legal problem which can not be solved in the conventional legal system governing contracts. In other words, the indicator's decision determines the effect and formation of the contracts in the face-to-face or written contracts but electronic decision through computer information network is established the working process of electronic signals-electronic contracts are not only difficult to separate the decision-making process but questioned to be solved by the theory of the general legal action. Ministry of Transportation is scheduled to introduce real estate sales and lease contract using a variety of electronic devices such as computer, tablet PC, smart phones and so on without a paper contract. This system is conducted to global expansion of Seoul in demonstration zone on May 8, 2016 and will be implemented nationwide in the second half of 2017. Electronics contract Real estate has some benefits because made by linking electronic contract system and the electronic registration system - the economic effects discounts on various kinds of fees, the prevention from real estate fraud beforehand and the solution to the complexity of the process the seller and the buyer visits The Real estate agency. However, it has some problem- the disorder in the real estate contract market, the occurrence of the real estate agency accident and the author of the electronic real estate contracts have limited only to realtor. In this paper, I suggest the activation plan to search for establishment and effect of electronic contracts and declaration of intention in electronic depending on the Electronic Contract Real Estate system.

• Journal of the Korea Institute of Building Construction
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• v.11 no.2
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• pp.171-180
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• 2011

As high-rise and irregularly shaped building structures have become a trend at home and abroad, BIM technology is now being developed and accepted widely. However, the BIM data and information generated in the design phase cannot be actively reutilized in the construction stage. This is because the major interests of construction companies include working process and cost estimation, while there is not usually enough BIM data created to support these activities. In order to resolve this issue, we need to set up BIM modeling guides that make it possible to extract correct quantity take-off from BIM data. Quality checks are also necessary to ensure that the resulting BIM data is correct. This study suggests ways of securing BIM quality for correct quantity take-off, which is critical for BIM technology applied to the building construction process and its cost estimation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.1-6
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• 2014

The IoT (Internet of Things) is considered as a core technology to realize interconnected world. At this, companies composing ICT industry and standard organizations make efforts to accelerate it. IETF CoRE(Constrained RESTful Environment) working group standardized CoAP (Constrained Application Protocol) for the constrained device. CoAP has RESTful architecture and CoAP option is provided to use forward-proxy. The forward-proxy is used to translate protocol and perform requests on behalf of the client. However, communication between Internet based client and LLN(Low-power and Lossy Network) based CoAP server architecture has limitations to deploy real IoT service. In this architecture, problems like response delay, URI assignment and DoS attack can be occurred. To solve these problems, we propose the reverse-proxy based system. We consider both of static IoT and mobility IoT environments. Finally, our proposed system is expected to provide efficient IoT service.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.47-55
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• 2019

The robot is the creation of new markets and various cooperation according to the manufacturing paradigm shift. Cooperative management easy for existing industrial robots, robots work on productivity, manpower to replace the robot in every industry cooperation for the purpose of and demand increases.to exist But the industrial robot at the scene of the cooperation working due to accidents are frequent, threatening the safety of the operator. Of industrial site is configured with a robot in an environment ensuring the safety of the operator to and confidence to communicate that can do the possibility of action.Robot guard system of the need for development cooperation. The robot's cooperation through the sensors and computer vision task within a radius of the double to prevent accidents and accidents should reduce the risk. International protocol for a variety of industrial production equipment and communications opc ua system based on ultrasonic sensors and cnn to (Convolution Neural Network) for video analytics. We suggest the cooperation with the robot guard system. Robots in a proposed system is unsafe situation of workers evaluating the possibility of control.

• Journal of Construction Engineering and Project Management
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• v.6 no.2
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• pp.1-7
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• 2016

Construction in the UK is the second most dangerous industry in terms of fatal and minor injuries according to the 2014 report of HSE. The use of mobile devices such as iPad, Tablets and Smart phones on the live construction projects is also on the increase in the UK due to the 2016 - Level 2 BIM (Building Information Modelling) implementation target, set by the UK Government. Hence, the use of such devices may become a distraction from work activities on the construction sites and will cause a major risk to the end users. The subject of improving safety of BIM use is widely researched, but there is a gap in knowledge about the actual use of the mobile devices and perception of 'Site BIM', on the construction site activities. The main gap identified in the 'Site BIM' is the health and safety aspect of using such devices on the construction sites. A safer way of working with such devices needs to be identified to avoid any potential site hazards and fatalities before the widespread use of the devices are found on the construction projects. In that context, the paper is aimed to highlight the safety issues that are required to address for the successful implementation of the mobile devices for safer use of the 'Site BIM'. Questionnaire survey was used to collect the site information among construction professionals in the UK. The survey findings suggested that a proactive approach may be helpful to stop potential hazards and risks causing by the use of mobile devices and potential measures need to be identified before any injuries and incidents occur. The paper concludes that training, changing size of mobile devices and ensuring a separate induction training for 'Site BIM' tools will improve the health and safety of the end users of the mobile devices at the live construction sites.

• Spatial Information Research
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• v.21 no.3
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• pp.1-10
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• 2013

Indoor space is a new horizon of spatial information services. With recent progress of indoor positioning technologies and mobile devices such as smart phones, indoor spatial information services become available and an emerging market. Accordingly, exchanging and sharing indoor spatial information between independent services become an important issue. For this reason, a standardization working group, called IndoorGML has been launched last year in OGC with the aim of publishing IndoorGML standard by September, 2013. Its primary goal is to provide a framework for representing network topology in indoor space, which is a fundamental element of indoor LBS. In this paper, we will explain the basic concepts of indoorGML and discuss the modeling issues. And several application use-cases of IndoorGML will be also presented in this paper.