• International journal of advanced smart convergence
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• v.9 no.2
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• pp.157-163
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• 2020

Recently the blockchain technology has been actively studied due to its great potentiality. The smart contract is a key mechanism of the blockchain system. Due to the short history of the smart contract, many issues have not been solved yet. One main issue is vulnerability and another main issue is cost optimization. While the vulnerability of smart contract has been actively studied, the cost optimization has been rarely studied. In this paper, we propose two cost optimization methods for smart contracts running on the blockchain system. Triggering a function in a smart contract program code may require costs and it is repeated continuously. So the minimization of costs required to trigger a function of smart contract while maintaining the performance equally is very important. The proposed two methods minimize the usage of expensive permanent variables deployed on the blockchain system. We apply the proposed two methods to three prevalent blockchain platforms: Ethereum, Klaytn and Tron. Evaluation experiments verify that the proposed scheme significantly reduces the costs of functions in the smart contract written with Solidity.

• International Journal of Computer Science & Network Security
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• v.22 no.2
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• pp.139-144
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• 2022

The smart cities are evolving constantly and are responsible for the current transformation of cities and countries into a completely connected network of information and technology This interconnected network of a huge number of smart devices is capable of exchanging complex information and provides tremendous support including enhanced quality of life within urban locations. Unfortunately this set-up is vulnerable to security attacks and requires the widespread ubiquitous network to authorize access through privacy and thus offer security in order to ensure civilian participation in a country. The smart network should benefit the individuals of the country by developing potential strategies to protect the smart cities and their participating entities from the unauthorized attacks. Trustworthy data sharing strategies based on the utilization of advanced technology features via smart communication network could solve some issues of privacy and security. This paper presents the challenges and issues related to protection and highlights the important aspects of securing the smart cities and its components. It also presents the role of cloud security for building a secure smart city.

• Journal of Digital Convergence
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• v.9 no.5
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• pp.99-111
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• 2011

Nowadays, the rapid progress and worldwide use of smart-media(SNS) has resulted in coming of the smart media convergence age. In practice, however, the effectiveness of smart media convergence society is limited by the difficulties of using it, which include accessibility, waiting for loading, clutter, old information, privacy risks, expensive communication, etc. The conquest of these difficulties must be policy target of broadcasting and telecommunication for high quality of communication life. From this perspective, this paper proposes a new policy of broadcasting and telecommunication based on the dynamic quality of life for the smart media convergence society. This smart convergence policy will not promote only the development and production of smart media contents but also its stable supply and it will secure the accessibility and privacy. In conclusion, this paper reveals that the components of quality of life are important elements of broadcasting and communication policies which will eventually lead to the popular use of smart media and enhance its quality.

• Journal of Digital Convergence
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• v.11 no.3
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• pp.33-40
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• 2013

The smart media has changed the patterns of advertising information consumption and media usage behavior drastically. The smart advertisements, however, have failed to perform as sophisticated as the smart devices carried out. In this respect, this study is designed to figure out the current situation and the ecosystem of smart advertising and to prepare its activation plan through a survey(FGI), which will be able to give policy suggestions about smart media and advertising. In conclusion, this study points out that the proliferation of smart advertising needs to install "Smart Media Representative" which provides independable decisions on the regulation of smart advertising, the system of price, standardization of advertising, the development of various forms of advertisements, the scientific measurement of the effectiveness, the protection of privacy, professional manpower training, etc.

• Journal of Information Technology Applications and Management
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• v.20 no.4
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• pp.151-164
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• 2013

According to the development of smart technologies such as smart phones, tablet PC, and SNS communication, the necessity of smart work that can change the working environments in organizations has been emphasized. However, while there are many organizations that wish to adopt smart technologies, there are those that have been skeptical until now about its potential success. Leaders may especially have different viewpoints concerning the efficacy and effectiveness of smart work depending on the industries, characteristics of the work, etc. Therefore, this research looks to investigate whether there may be differences between leaders (manager, project manager, supervisor, etc.) and non-leaders (team member, staff, etc.) group in accepting smart working through empirical and exploratory approaches.

• Computers and Concrete
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• v.23 no.6
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• pp.399-408
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• 2019

Structural health monitoring is important for the safety of lives and asset management. In this study, numerical models were developed for the piezoresistive behavior of smart concrete based on finite element (FE) method. Finite element models were calibrated with experimental data collected from compression test. The compression test was performed on smart concrete cube specimens with 75 mm dimensions. Smart concrete was made of cement CEM II 42.5 R, silica fume, fine and coarse crushed limestone aggregates, brass fibers and plasticizer. During the compression test, electrical resistance change and compressive strain measurements were conducted simultaneously. Smart concrete had a strong linear relationship between strain and electrical resistance change due to its piezoresistive function. The piezoresistivity of the smart concrete was modeled by FE method. Twenty-noded solid brick elements were used to model the smart concrete specimens in the finite element platform of Ansys. The numerical results were determined for strain induced resistivity change. The electrical resistivity of simulated smart concrete decreased with applied strain, as found in experimental investigation. The numerical findings are in good agreement with the experimental results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.8
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• pp.3958-3971
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• 2016

With Internet of Things (IoT) technology, home environment becomes smarter than ever. Not only smart devices such as smart phone or smart TV, but also various IoT devices including sensor, smart thermostat, and smart scale has now become very common on the market. These devices have connectivity to the Internet, so that user can read data from the device or control the device using Internet technology. However, due to diversity of smart home requirements, device collaboration in smart home remains a challenging task still. Usually smart home is built with various technologies to fulfill its own purpose, and these purposes cover very wide area from controlling low-power sensor devices to controlling high-performance devices like smart TV and smart phone. This variety of smart home requirements makes smart home very complicated due to mixed network architecture, protocol and technology. In this paper, a framework to enable managing and collaborating heterogeneous IoT devices in smart home environment is proposed. Several programming models are defined in the proposed framework to make application development for heterogeneous devices more intuitive. The proposed framework has been implemented as a web service, and a case study with real-world smart home IoT devices is presented.

• Journal of the Korea Convergence Society
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• v.10 no.7
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• pp.33-37
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• 2019

Nowadays, the needs for linking smart devices are growing fast because of wide spread of smart devices such as smart TV, smart phones, smart pad and so on. This paper presents a game framework for linking smart TV and smart phones and proves its applicability by developing an example contents. The problem of connection between smart devices is basically a problem of connection between heterogeneous devices. The problem is that data transmission and reception between heterogeneous devices must be considered. Therefore, the core data is implemented by adopting the concept of cloud computing and storing it in a server, and in a smart TV, playing the game by using this data. The proposed framework could be applied to a lot of applications such as computer games.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.2
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• pp.134-144
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• 2007

In this study, a smart sensor unit is developed by using the smart sensor technology that is being rapidly developed in recent years for structural health monitoring system, and its performance is evaluated through various experiments, and also, damage detection experiment is performed on a model structure. This paper as the first half of this study contains the development and performance evaluation of the smart sensor. In the latter half of this study, structure damage detection experiment is performed for the application of verified smart sensor unit into structural health monitoring, and it is compared with a wire measurement system. The smart sensor is developed by using high-power wireless modem, MEMS Sensor and AVR microcontroller, and an embedded program is also developed for the control and operation of the sensor unit. To verify the performance of the smart sensor, many experiments are performed for sensitivity and resolution analysis tests, data acquisition by using cantilever beam and shaker, and on-site application using actual bridge. As a result, the smart sensor proves to be satisfactory in its performance.

• Smart Structures and Systems
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• v.4 no.3
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• pp.367-389
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• 2008

Shape Memory Alloys (SMAs) are unique materials with a paramount potential for various applications in bridges. The novelty of this material lies in its ability to undergo large deformations and return to its undeformed shape through stress removal (superelasticity) or heating (shape memory effect). In particular, Ni-Ti alloys have distinct thermomechanical properties including superelasticity, shape memory effect, and hysteretic damping. SMA along with sensing devices can be effectively used to construct smart Reinforced Concrete (RC) bridges that can detect and repair damage, and adapt to changes in the loading conditions. SMA can also be used to retrofit existing deficient bridges. This includes the use of external post-tensioning, dampers, isolators and/or restrainers. This paper critically examines the fundamental characteristics of SMA and available sensing devices emphasizing the factors that control their properties. Existing SMA models are discussed and the application of one of the models to analyze a bridge pier is presented. SMA applications in the construction of smart bridge structures are discussed. Future trends and methods to achieve smart bridges are also proposed.