• Steel and Composite Structures
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• v.4 no.6
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• pp.471-487
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• 2004

Modular steel scaffolds are commonly used as supporting scaffolds in building construction, and traditionally, the load carrying capacities of these scaffolds are obtained from limited full-scale tests with little rational design. Structural failure of these scaffolds occurs from time to time due to inadequate design, poor installation and over-loads on sites. In general, multi-storey modular steel scaffolds are very slender structures which exhibit significant non-linear behaviour. Hence, secondary moments due to both $P-{\delta}$ and $P-{\Delta}$ effects should be properly accounted for in the non-linear analyses. Moreover, while the structural behaviour of these scaffolds is known to be very sensitive to the types and the magnitudes of restraints provided from attached members and supports, yet it is always difficult to quantify these restraints in either test or practical conditions. The problem is further complicated due to the presence of initial geometrical imperfections in the scaffolds, including both member out-of-straightness and storey out-of-plumbness, and hence, initial geometrical imperfections should be carefully incorporated. This paper presents an extensive numerical study on three different approaches in analyzing and designing multi-storey modular steel scaffolds, namely, a) Eigenmode Imperfection Approach, b) Notional Load Approach, and c) Critical Load Approach. It should be noted that the three approaches adopt different ways to allow for the non-linear behaviour of the scaffolds in the presence of initial geometrical imperfections. Moreover, their suitability and accuracy in predicting the structural behaviour of modular steel scaffolds are discussed and compared thoroughly. The study aims to develop a simplified and yet reliable design approach for safe prediction on the load carrying capacities of multi-storey modular steel scaffolds, so that engineers can ensure safe and effective use of these scaffolds in building construction.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.5
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• pp.95-105
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• 2002

This paper describes an efficient method to implement a hardware circuit of RSA public key cryptographic algorithm, which is important to public-key cryptographic system for an authentication, a key exchange and a digital signature. The RSA algorithm needs a modular exponential for its cryptographic operation, and the modular exponential operation is consists of repeated modular multiplication. In a numerous algorithm to compute a modular multiplication, the Montgomery algorithm is one of the most widely used algorithms for its conspicuous efficiency on hardware implementation. Over the past a few decades a considerable number of studies have been conducted on the efficient hardware design of modular multiplication for RSA cryptographic system. But many of those studies focused on the decrease of operating time for its higher performance. The most important thing to design a hardware circuit, which has a limit on a circuit area, is a trade off between a small circuit area and a feasible operating time. For these reasons, we modified the Montgomery algorithm for its efficient hardware structure for a system having a limit in its circuit area and implemented the refined algorithm in the IESA system developed for ETRI's smart card emulating system.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.484-491
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• 2022

A paradigm shift in teaching modular construction in higher education and K-12 is proposed as a means to increase the future adoption of the modular construction technique. To this effect, a new education module is presented to STEM educators. This education module is based on LEGOs and directed towards educators in the architecture, engineering, and construction (AEC) industry. The main objectives of the education module are to increase interest and knowledge of modular construction, acknowledge the benefits of using 3D design with 4D scheduling, and create a simulating hands-on educational opportunity. The education module is designed to allow participants to experience a hands-on simulation of modular construction and stick-built construction through building a LEGO project. Participants are challenged to find the advantages and disadvantages in both construction systems first-hand and record their findings. Results are presented from the preliminary testing of this education model on a group of construction management students at the University of Nevada, Las Vegas. Overall, the survey results showed that the LEGO education module was successful at achieving the project's three main objectives: 1) increasing the participants' interest and knowledge of modular construction through an interactive project; 2) increasing the participants' understanding of the benefits of 3D design with 4D scheduling over the use of 2D drawings; and 3) creating a simulating hands-on educational opportunity to help participants compare modular construction to stick-built construction. In the end, this proposed a new LEGO education module addressing the problems identified from this study with more participants.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.164-165
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• 2015

Modular construction technique is an adaptation of factory-based mass production concept in ordinary manufacturing industries to construction industry and it assumes that panels, units, etc. are fabricated in factories and assembled in construction sites. Given its structural limitations, modular construction technique is primarily used in low-story buildings whose maximum height is usually five stories, but researchers are actively studying possible adaptation of modular construction technique to high-rise building designs these days as in the case of infill-type modular construction design. Infill-type modular construction technique, most frequently used in high-rise building construction projects, completes frame construction first in reinforced concrete structures and fills unit modules in such structures. However, infill-type modular construction technique leads to longer construction schedule accompanying increase in construction cost, cost overrun due to additional of temporary work, and possible damage to units in the wake of facility construction. Accordingly, this study is performed as a basic study for the development of bottom-up infill-type modular construction technique intended to construct structural frames and fill in units sequentially in a bid to address such drawbacks of current infill-type modular construction technique.

• The Journal of Economics, Marketing and Management
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• v.12 no.4
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• pp.13-25
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• 2024

Purpose: Korea's construction industry has faced declining productivity and quality issues due to labor-intensive onsite construction and variables like weather, material price fluctuations, and labor shortages. The modular housing industry, introduced in Korea in 2003, offered benefits like reduced construction time and enhanced productivity through offsite manufacturing. However, its adoption remains limited due to high costs, quality concerns, and low consumer acceptance. Research Design, Data, and Methodology: This study explores the feasibility and impact of implementing smart factory technologies in the modular housing industry to overcome these barriers. Using survey data from 179 construction industry experts, the study employs frequency and regression analysis to identify key factors influencing the adoption of modular housing and the effectiveness of smart factories. Findings suggest that government-led educational programs and strong policy support are essential for successful implementation, enhancing productivity, reducing costs, and improving quality. Conclusions: The study emphasizes the need for standardization of modular housing, deregulation of relevant laws, and increased public awareness to stimulate market growth and innovation. Policy recommendations include financial support for modular manufacturers transitioning to smart factories, ensuring stable supply volumes, and promoting the benefits of modular housing to consumers. Integrating smart factory technologies can lead to significant advancements in the modular housing industry, contributing to the sustainable development and modernization of Korea's construction sector.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.153-155
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• 2009

Cleaning robot system consists of four parts; navigation system for moving of robot, cleaning system, power system, and main system with cleaning algorithm. Navigation system is the most expensive part because it has motors and sensors which is high price. Navigation system is also essential to service robot system, but user should buy two systems which are service robot system and cleaning robot system. If it is possible to share navigation system, user can save money. In this paper, we design the cleaning robot system based on modular architecture.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.2
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• pp.51-58
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• 2014

As WSNs(Wireless Sensor Networks) are being deployed widely in diverse application areas, their management and maintenance become more important. Recent sensor node software takes modular software architectures in pursuit of flexible software management and energy efficient reprogramming. To realize an flexible and efficient modular architecture particularly on resource constrained mote-class sensor nodes that are implemented with MCUs(Micro-Controller Units) of a single address space. an appropriate module linking model is essential to resolve and bind the inter-module global symbols. This paper identifies a design space of module linking model and respectively their implementation frameworks. We then establish a taxonomy for module linking models by exploring the design space of module linking models. Finally, we suggest an implementation framework respectively for each module linking model in the taxonomy. We expect that this work lays the foundations for systematic innovation toward more flexible and efficient modular software architectures for WSNs.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.81-82
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• 2014

Modular housing has many advantages such as economy, flexibility and reusability. The domestic modular housing of a continuous stacking method has been built in military facilities, and dormitories. However, there is a limit to present diversity of low-rise multi-family housing. A cross stacking method is a way to pursue diversity of that but there is a difficulty to apply it owe to lack of cases and related technologies. Therefore, the purpose of this study is to suggest application techniques in design phase of applying the crossing stacking method in advance.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.278-280
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• 2013

To minimize construction quantity of nuclear facility, it is required to reduce reinforcing bar amount and solve reinforcing bar concentration and for this, it is necessary to develop application design technology and modular of high strength reinforcing bar. Hence, KHNP reduces excessive reinforcing bar amount which can cause possibility of poor construction of concrete through design standard development and modular of nuclear facility structure using high strength reinforcing bar to raise economics and has its purpose to maintain high-level safety and durability as they are.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.9 no.1
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• pp.135-146
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• 1999

Most public key cryptosystems are constructed based on a modular exponentiation, which is further decomposed into a series of modular multiplications. We design a new systolic array multiplier to speed up modular multiplication using Montgomery algorithm. This multiplier with simple circuit for each processing element will save about 14% logic gates of hardware and 20% execution time compared with previous one.