• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.3
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• pp.515-518
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• 2019

The performance of Elliptic Curves Cryptosystem(ECC) is dominated by the modular multiplication since the elliptic curve scalar multiplication consists of the modular multiplication in projective coordinates. In this paper, we propose a new method that combines the Karatsuba-Ofman multiplication method and a new modular reduction algorithm in order to improve the performance of the modular multiplication for NIST p224 in the FIPS 186-4 standard. The proposed method leads to a running time improvement for computing the modular multiplication about 25% faster than the previous methods. The results also show that the method can reduce the arithmetic complexity by half when compared with traditional implementations on the standpoint of the modular reduction.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.11
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• pp.43-52
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• 2019

The purpose of this study is to suggest the use of modular construction method in order to promote the dissemination of the Health Life Support Center of the government, and to suggest the modular unitification and modularization plan for the necessary space data in the initial stage. By analyzing the floor plans of the 50 case projects currently in operation, the 28 required spaces and their spatial proximities are determined. Base on spatial proximities, each space is unitificated into a modular unit and modularized into a modular modules were integrated to modular proposals. As a result of this study, 13 unitificated modular unit floor planes and 3 modularized module floor planes including the staircase unit were proposed. However, future study have needed to study how to apply them to different actual sites and how to reduce cost.

• Advances in concrete construction
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• v.15 no.6
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• pp.377-389
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• 2023

In this study, an improved modular arch system with the lower arch space composed of a precast arch block and an outrigger was proposed as an underground culvert, and its applicability and structural behaviors were confirmed. This modular arch culvert structure with vertical walls was designed using precast blocks and by adjusting the placement spacing of concrete blocks to the upper part form an arch shape and the lower part form a vertical wall shape, based on previously researched modular arch systems. Owing to the vertical wall of the proposed modular arch system, it is possible to secure a load-carrying capacity and an arch space that can sufficiently resist the earth pressure generated from the backfill soil and loading on the arch system. To verify the structural characteristics, and applicability of the proposed modular precast arch culvert structure, a full-scale modular culvert specimen was fabricated, and a loading test was conducted. By examining its construction process and loading test results, the applicability and constructability of the proposed structure were analyzed along with its structural characteristics. In addition, its the structural predictability and safety for the applicability were evaluated by comparing the construction process and loading test results with the FE analysis results.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.291-292
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• 2021

In modular construction, it is insufficient for safety management of workers, and workers are still exposed to the risk of accidents due to work at high places for lifting and assembly work in modular construction sites. Therefore, it is necessary when preventive safety management through risk management of workers on modular construction sites. This study is a basic study for the risk assessment(checklist) of modular construction, and the purpose of this study is to analyze the risk factors of the module lifting work at the modular construction site. It is intended to identify the hazard risk factors and improvement measures of the existing lifting operation, by analyzing the case of the risk assessment of the existing RC method, and to identify the risk factors for each work process when lifting the module. In the future, the results of this study are expected to be utilized in the development of checklists for risk assessment as safety management plan for modular construction sites.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.571-578
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• 2022

Modularization in a high-rise building is different from a small building, as it is exposed to more lateral forces like wind and earthquakes. The integrity, robustness, and overall stability of the modules and their performance is based on the joining techniques and strong structural systems. High lateral stiff construction structures like concrete shear walls and frames, braced steel frames, and steel moment frames are used for the stability of high-rise modular buildings. Similarly, high-rise stick-built buildings have concrete cores and perimeter frames for lateral load strength and stiffness. Methods for general steel-concrete connections are available in many works of literature. However, there are few modular-related papers describing this connection system in modular buildings. This paper aims to review the various research and practice adopted for steel-to-concrete connections in construction and compare the methods between stick-built buildings and modular buildings. The literature review shows that the practice of steel module-to-concrete core connection in high-rise modular buildings is like outrigger beams-to-concrete core connection in stick-built framed buildings. This paper concludes that further studies are needed in developing proper guidelines for a steel module-to-concrete core connection system in high-rise modular buildings.

• Journal of Fashion Business
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• v.23 no.1
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• pp.49-63
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• 2019

The purpose of this study is to examine the characteristics of modular design observed in Korean traditional clothing. Modular design, which is one of the noticeable characteristics of modern fashion design emerged in the 20th century. This study analyzed the Korean traditional culture to investigate the characteristics that show similarities to the modular system in design. A traditional Korean house is composed of small structures called 'chae'. A traditional Korean building is composed of a basic unit space called 'kan', and the rooms are divided and recombined. Korean traditional interior design shows furniture, bedding and art works that could be used, folded then stored. Korean cuisine is served in combination with small dishes. Korean letters are combined in square shaped form to make writing and printing easy. Korean traditional clothing has a way of washing where clothing are disassembled, washed and then re-stitched. The pattern pieces are made to be rectangular shaped so that the fabric pieces can be kept in shape during washing. The rectangular shaped pattern pieces can be replaced and reused after washing. Tops and bottoms could be interchanged for color-coordination, because the shapes of the clothing were standardized. These features exhibit modular system in Korean traditional clothing design. Modular system design has common characteristics which have basic modules, pursue practical purpose, have interchangeability adapted to circumstances, and could be disassembled and re-combined. Korean traditional clothing illustrates different ways of practicing modular system, but has some common features to contemporary modular fashion design.

• Journal of the Regional Association of Architectural Institute of Korea
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• v.21 no.5
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• pp.133-140
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• 2019

Building Information Modeling (BIM) and modular construction are regarded as important technologies that could contribute to overcoming the crisis faced by the construction industry. However, BIM uptake in current modular construction projects is limited. Moreover, there are no specific guidelines to support decision-making regarding the application of BIM in modular construction projects. Therefore, this study aims to analyze the possibility for BIM uptake in each phase of modular construction projects in Korea. Initially, the literature detailing on BIM uptake cases in modular construction projects was reviewed. The detailed work and activities for each phase of a modular project were analyzed via a questionnaire targeting domestic modular experts, to derive items requiring improvement due to errors or changes occurring in the actual project. Ten realistic BIM uptake items were derived, reflecting the results of literature review and expert interviews. Then, the BIM uptake items in each phase were analyzed in terms of necessity and efficiency via a second questionnaire using five-point Likert scales. Finally, the BIM utilization index (BIM UI) of the BIM uptake items was suggested as a priority measure. As a result, the BIM UI of "3D coordination" (U2), "design authoring and reviews for off-site fabrication" (U3), and "detailed 3D modeling for off-site fabrication" (U4), were assigned the highest priority. The results of this study can be used as guidelines to support decision-making regarding the application of BIM in modular construction projects.

• Journal of The Korea Institute of Healthcare Architecture
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• v.28 no.3
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• pp.7-16
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• 2022

Purpose: This study aims to establish the basic directions of the modular airborne infection isolation(AII) ward. Considering a specific function and purposed use as a modular AII ward, it is a chance to derive an address of current modular technology by overview the limitation and improvement of the existing modular architecture. Methods: In addition to the literature analysis on the configuration system of mobile hospitals, research cases on the operational effectiveness of the domestic and foreign mobile construction systems are analyzed. Results: In order to meet the various and strict space guidelines of the AII ward and a chance to improve limitations of uniformed existing modulars, AII modular the negative pressurized care setting should be minimized a structural restriction for reflecting its system on a architectural plan. For this unique requirements, it could be possible to apply various space boxes called infill box which needs to secure a large-scale space. So, a rahmen structure system could be adaptable for this purpose. A dead space between beams of the rahmen structure is to be used for MEP installation. Partial separation, dismantling, and repair should be possible by separating the MEP and infill box from the structure. The infill box must keep 3.5m width under the current Road Traffic Act. Implications: It is necessary to utilize and develop an improved construction method that can reduce the problems of existing steel modular and PC modular.

• Korean Journal of Construction Engineering and Management
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• v.19 no.6
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• pp.124-134
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• 2018

Despite the many advantages of modular housing, low preference for modular housing for consumers who are familiar with RC structure leads to high construction cost of modular housing. The cost of modular buildings is about 130% of that of RC structures, so it is urgent to secure economical efficiency of modular buildings. Therefore, in this study, after calculating the savings amount of modular housing by type of construction work, economic analysis was conducted from a long - term perspective. In order to carry out the research, the authors compiled and analyzed the material cost, labor cost, and expenses incurred by each type of work by reclassifying the statement of the modular housing into the factory production and the site installation. After that, Pareto diagrams were created to find a core work that is included in the cost ratio of about 80%, and selected it as a cost reduction subject. Based on the assumption that the market size of domestic modular housing is similar to the level of modular advanced countries such as Japan and European countries, six cost reduction methods were set up that reflects the characteristics of the modular construction method and used for the expert interviews. Cost saving potentials in percentage from the interview were converted to the amount of savings that can be achieved by each type of method when applying the method. Finally, the findings of the study are expected to suggest long-term directions for technical development for modular construction and cost savings.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.7 no.2
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• pp.73-92
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• 1997

A modular exponentiation( E$M^{$=varepsilon$}$mod N) is one of the most important operations in Public-key cryptography. However, it takes much time because the modular exponentiation deals with very large operands as 512-bit integers. Modular exponentiation is composed of repetition of modular multiplications, and the number of repetition is the same as the length of the addition-chain of the exponent(E). Therefore, we can reduce the execution time of modular exponentiation by finding shorter addition-chain(i.e. reducing the number of repetitions) or by reducing the execution time of each modular multiplication. In this paper, we propose an addition-chain heuristics and two fast modular multiplication algorithms. Of two modular multiplication algorithms, one is for modular multiplication between different integers, and the other is for modular squaring. The proposed addition-chain heuristics finds the shortest addition-chain among exisiting algorithms. Two proposed modular multiplication algorithms require single-precision multiplications fewer than 1/2 times of those required for previous algorithms. Implementing on PC, proposed algorithms reduce execution times by 30-50% compared with the Montgomery algorithm, which is the best among previous algorithms.