• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권6호
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• pp.2152-2170
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• 2014

With advances in smart and ICT(information and communication technology) technologies, our life style has been changing dramatically. Now everybody can enjoy the benefits of such technologies in every aspect of his/her daily life. Currently more and more people are trying to have smart devices such as smart phones and tablet PCs so that smart devices become the bare necessities. New smart technologies have created a new concept called smart learning in education area. As educational smart contents become popular, we need quality standards for the contents. Those standards are essential for evaluating the smart contents and suggesting guidance for future smart contents production. Although there are some standards for the existing e-learning environments, to our best knowledge, there are no standards for educational smart contents in the literature. The purpose of this paper is to develop quality standards for educational smart contents. The proposed quality standards are based on the existing quality standards in e-learning environments and include some characteristics of smart learning. For development of quality standards, wide experts group from academy and industry are selected and surveyed. Their responses are analyzed based on thorough statistical analysis so that final quality standards for educational smart contents are developed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권11호
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• pp.5625-5641
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• 2017

Certificateless public key cryptography resolves the certificate management problem in traditional public key cryptography and the key escrow problem in identity-based cryptography. In recent years, some good results have been achieved in speeding up the computation of bilinear pairing. However, the computation cost of the pairing is much higher than that of the scalar multiplication over the elliptic curve group. Therefore, it is still significant to design cryptosystem without pairing operations. A multi-signer universal designated multi-verifier signature scheme allows a set of signers to cooperatively generate a public verifiable signature, the signature holder then can propose a new signature such that only the designated set of verifiers can verify it. Multi-signer universal designated multi-verifier signatures are suitable in many different practical applications such as electronic tenders, electronic voting and electronic auctions. In this paper, we propose a certificateless multi-signer universal designated multi-verifier signature scheme and prove the security in the random oracle model. Our scheme does not use pairing operation. To the best of our knowledge, our scheme is the first certificateless multi-signer universal designated multi-verifier signature scheme.

• Smart Structures and Systems
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• 제5권4호
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• pp.357-367
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• 2009

Structural Health Monitoring (SHM), particularly remote monitoring, is an emerging field with great potential to help infrastructure owners obtain more and up-to-date knowledge of their structures. The methodology could provide supplemental information to guide the frequency and extent of visual inspections, and the possible need for maintenance. The instrumentation for a SHM system needs to be developed with longevity and the objectives for the system in mind. Sensors need to be selected for reliability and durability, sited where they provide the maximum information for the objectives, and where they can be accessed and replaced should the need arise over the monitoring period. With the rapid changes now occurring with sensors and software, flexibility needs to be in place to allow the system to be upgraded over time. Damage detection needs to be considered in terms of the type of damage that needs to be detected, informing maintenance requirements, and how detection can be achieved. Current vibration analysis techniques appear not yet to have achieved the necessary sensitivity for that purpose. Societal factors will influence the design of a SHM system in terms of the sophistication of the instrumentation and methodology employed.

• Smart Structures and Systems
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• 제6권3호
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• pp.239-262
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• 2010

Tube Lines has carried out a "knowledge and investigation programme" on the deep tube tunnels comprising the Jubilee, Northern and Piccadilly lines, as required by the PPP contract with London Underground. Many of the tunnels have been in use for over 100 years, so this assessment was considered essential to the future safe functioning of the system. This programme has involved a number of generic investigations which guide the assessment methodology and the analysis of some 5,000 individual structures. A significant amount of investigation has been carried out, including ultrasonic thickness measurement, detection of brickwork laminations using radar, stress measurement using magnetic techniques, determination of soil parameters using CPT, pressuremeter and laboratory testing, installation of piezometers, material and tunnel segment testing, and trialling of remote photographic techniques for inspection of large tunnels and shafts. Vibrating wire, potentiometer, electro level, optical and fibre-optic monitoring has been used, and laser measurement and laser scanning has been employed to measure tunnel circularity. It is considered that there is scope for considerable improvements in non-destructive testing technology for structural assessment in particular, and some ideas are offered as a "wish-list". Assessment reports have now been produced for all assets forming Tube Lines' deep tube tunnel network. For assets which are non-compliant with London Underground standards, the risk to the operating railway has to be maintained as low as reasonably practicable (ALARP) using enhanced inspection and monitoring, or repair where required. Monitoring techniques have developed greatly during recent years and further advances will continue to support the economic whole life asset management of infrastructure networks.

• Smart Structures and Systems
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• 제21권2호
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• pp.195-205
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• 2018

Research on Lamb wave-based damage identification in plate-like structures depends on precise knowledge of dispersive wave velocity. However, boundary reflections with the same frequency of interest and greater amplitude contaminate direct waves and thus compromise measurement of Lamb wave dispersion in different materials. In this study, non-reflecting boundaries were proposed in both numerical and experimental cases to facilitate time-frequency characterization of Lamb wave dispersion. First, the Lamb wave equations in isotropic and laminated materials were analytically solved. Second, the non-reflecting boundaries were used as a series of frames with gradually increased damping coefficients in finite element models to absorb waves at boundaries while avoiding wave reflections due to abrupt property changes of each frame. Third, damping clay was sealed at plate edges to reduce the boundary reflection in experimental test. Finally, the direct waves were subjected to the slant-stack and short-time Fourier transformations to calculate the dispersion curves of phase and group velocities, respectively. Both the numerical and experimental results suggest that the boundary reflections are effectively alleviated, and the dispersion curves generated by the time-frequency analysis are consistent with the analytical solutions, demonstrating that the combination of non-reflecting boundary and time-frequency analysis is a feasible and reliable scheme for characterizing Lamb wave dispersion in plate-like structures.

• 대한인간공학회지
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• 제30권1호
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• pp.169-177
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• 2011

The aim of this study is to review previous studies on human errors in the service delivery processes. Service industry is sharply growing in the advanced countries. Many people are looking for something to contribute to the service industry. Although there are many research topics related to service domain that human factors and ergonomics specialists can do contribute, a few researchers are studying such topics. This paper indicated how previous researches on human factors and human errors have addressed the service domain, in order to prompt human factor study on the service domain. A variety of sources were inspected for literature reviews, including books and journals of managements, medicine, psychology, consumer behavior as well as human factor and ergonomics. The characteristics of human errors in the service domain were investigated. Human error studies in several service sectors were summarized such as medical service, automotive service operation, travel agent service and call center service. Until now, human factors community was not much interested in human errors in service domain. However, there is much space to contribute to service domain; human error identification, human error analysis and control of human error. The research of human error in service domain can provide clues to improve service quality. This paper helps to guide to identify human error of service domain and to design service systems.

• 산업경영시스템학회지
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• 제38권2호
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• pp.1-7
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• 2015

As a measure of health, the percentage of body fat has been utilized for many ergonomist, physician, athletic trainers, and work physiologists. Underwater weighing procedure for measuring the percentage of body fat is popular and accurate. However, it is relatively expensive, difficult to perform and requires large space. Anthropometric techniques can be utilized to predict the percentage of body fat in the field setting because they are easy to implement and require little space. In this concern, the purpose of this study was to find a regression model to easily predict the percentage of body fat using the anthropometric circumference measurements as predictor variables. In this study, the data for 10 anthropometric circumference measurements for 252 men were analyzed. A full model with ten predictor variables was constructed based on subjective knowledge and literature. The linear regression modeling consists of variable selection and various assumptions regarding the anticipated model. All possible regression models and the assumptions are evaluated using various statistical methods. Based on the evaluation, a reduced model was selected with five predictor variables to predict the percentage of body fat. The model is : % Body Fat = 2.704-0.601 (Neck Circumference) + 0.974 (Abdominal Circumference) -0.332 (Hip Circumference) + 0.409 (Arm Circumference) - 1.618 (Wrist Circumference) + $\epsilon$. This model can be used to estimate the percentage of body fat using only a tape measure.

• 한국컴퓨터정보학회논문지
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• 제3권4호
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• pp.110-119
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• 1998

본 논문은 개방형 분산 Computing system에서 여러 분산 어플리케이션 프로그래머들에게 범용 암호 서비스 제공을 위한 C-API(Cryptographic-Application Program Interface) Mechanism개발에 대하여 설명한다. C-API Mechanism는 응용 프로그래머에게 공통적으로 사용 할 수 있는 암호 알고리즘 및 인터페이스를 제공함으로써 프로그래머가 암호 알고리즘을 알지 못하여도 분산 어플리케이션이 보안 서비스를 제공할 수 있다. 따라서,본 논문에서는 다양한 응용 환경 또는 시스템 하부구조에 독립적으로 사용될 수 있는 공용암호 서비스 구조를 설계하여 공통적으로 이용할 수 있도록 하였다. 이러한 구조는 응용 프로그래머에게 각종 암호화 관련서비스 및 키관리 서비스를 응용 프로그램과 운영체제의 제약없이 사용할 수 있는 장점이다.

• 한국조경학회지
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• 제34권5호
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• pp.14-23
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• 2006

Recently there have been great interest in the street landscapes, and numerous studies have been investigating shaping processes of urban landscapes, legal systems for scenery management, landscape preference and evaluation techniques. However, there are only few studies investigating how planting types influence on street landscape evaluation and how the relationships among street landscapes are. This study aims to make a guidelines which can be used for securing afforestation in urban settings and improving urban environment. In specific, the results of this study can provide guidelines for urban street design and the base knowledge for identifying appropriate requirements for better street landscapes. We identify factors which make shape certain images of street landscape, and draw physical factors influencing on visual appropriateness through visual landscapes evaluation process. To evaluate landscapes according to planting types, on-the-spot survey at 14 streets in Gang-Nam district were made. The district is under executing street improving projects and shows the most satisfying planting types. To evaluate street landscapes which people experience during their walking, 100m of continuous streets are chosen. The survey sites exclude streets with irregular pattern, are adjacent to large urban parks or are used as parking spaces in part. We evaluated 9 street landscapes classified into 1-line-planting, 2-line-planting and 3-line-planting on the basis of the location of planting and the planting methods.

• Industrial Engineering and Management Systems
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• 제13권2호
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• pp.231-249
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• 2014

This paper discusses a green supply chain with a manufacturer and a collection trader, and it proposes an optimal production planning for remanufacturing of parts in used products with quality classification errors made by the collection trader. When a manufacturer accepts an order for parts from a retailer and procures used products from a collection trader, the collection trader might have some quality classification errors due to the lack of equipment or expert knowledge regarding quality classification. After procurement of used products, the manufacturer inspects if there are any classification errors. If errors are detected, the manufacturer reclassifies the misclassified (overestimated) used products at a cost. Accordingly, the manufacturer decides to remanufacture from the higher-quality used products based on a remanufacturing ratio or produce parts from new materials. This paper develops a mathematical model to find how quality classification errors affect the optimal decisions for a lower limit of procurement quality of used products and a remanufacturing ratio under the lower limit and the expected profit of the manufacturer. Numerical analysis investigates how quality of used products, the reclassification cost and the remanufacturing cost of used products affect the optimal production planning and the expected profit of a manufacturer.