• International conference on construction engineering and project management
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• 2024.07a
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• pp.152-159
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• 2024

Cracks in structural materials present a critical challenge to infrastructure safety and long-term durability. Timely and precise crack detection is essential for proactive maintenance and the prevention of catastrophic structural failures. This study introduces an innovative approach to tackle this issue using U-Net deep learning architecture. The primary objective of the intended research is to explore the potential of U-Net in enhancing the precision and efficiency of crack detection across various concrete crack detection under various environmental conditions. Commencing with the assembling by a comprehensive dataset featuring diverse images of concrete cracks, optimizing crack visibility and facilitating feature extraction through advanced image processing techniques. A wide range of concrete crack images were collected and used advanced techniques to enhance their visibility. The U-Net model, well recognized for its proficiency in image segmentation tasks, is implemented to achieve precise segmentation and localization of concrete cracks. In terms of accuracy, our research attests to a substantial advancement in automated of 95% across all tested concrete materials, surpassing traditional manual inspection methods. The accuracy extends to detecting cracks of varying sizes, orientations, and challenging lighting conditions, underlining the systems robustness and reliability. The reliability of the proposed model is measured using performance metrics such as, precision(93%), Recall(96%), and F1-score(94%). For validation, the model was tested on a different set of data and confirmed an accuracy of 94%. The results shows that the system consistently performs well, even with different concrete types and lighting conditions. With real-time monitoring capabilities, the system ensures the prompt detection of cracks as they emerge, holding significant potential for reducing risks associated with structural damage and achieving substantial cost savings.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2335-2347
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• 2023

As medical facilities are usually built at urban areas, special concrete aggregates and evaluation methods are needed to optimize the design of concrete walls by balancing density, thickness, material composition, cost, and other factors. Carbon treatment rooms require a high radiation shielding requirement, as the neutron yield from carbon therapy is much higher than the neutron yield of protons. In this case study, the maximum carbon energy is 430 MeV/u and the maximum current is 0.27 nA from a hybrid particle therapy system. Hospital or facility construction should consider this requirement to design a special heavy concrete. In this work, magnetite is adopted as the major aggregate. Density is determined mainly by the major aggregate content of magnetite, and a heavy concrete test block was constructed for structural tests. The compressive strength is 35.7 MPa. The density ranges from 3.65 g/cm³ to 4.14 g/cm³, and the iron mass content ranges from 53.78% to 60.38% from the 12 cored sample measurements. It was found that there is a linear relationship between density and iron content, and mixing impurities should be the major reason leading to the nonuniform element and density distribution. The effect of this nonuniformity on radiation shielding properties for a carbon treatment room is investigated by three groups of Monte Carlo simulations. Higher density dominates to reduce shielding thickness. However, a higher content of high-Z elements will weaken the shielding strength, especially at a lower dose rate threshold and vice versa. The weakened side effect of a high iron content on the shielding property is obvious at 2.5 µSv=h. Therefore, we should not blindly pursue high Z content in engineering. If the thickness is constrained to 2 m, then the density can be reduced to 3.3 g/cm³, which will save cost by reducing the magnetite composition with 50.44% iron content. If a higher density of 3.9 g/cm³ with 57.65% iron content is selected for construction, then the thickness of the wall can be reduced to 174.2 cm, which will save space for equipment installation.

• Asia pacific journal of information systems
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• v.24 no.2
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• pp.211-232
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• 2014

Recently, there is a growing interest toward social commerce using SNS(Social Networking Service), and the size of its market is also expanding due to popularization of smart phones, tablet PCs and other smart devices. Accordingly, various studies have been attempted but it is shown that most of the previous studies have been conducted from perspectives of the users. The purpose of this study is to derive user-centered CSF(Critical Success Factor) of social commerce from the previous studies and analyze the CSF perception gap between social commerce service providers and users. The CSF perception gap between two groups shows that there is a difference between ideal images the service providers hope for and the actual image the service users have on social commerce companies. This study provides effective improvement directions for social commerce companies by presenting current business problems and its solution plans. For this, This study selected Korea's representative social commerce business Ticket Monster, which is dominant in sales and staff size together with its excellent funding power through M&A by stock exchange with the US social commerce business Living Social with Amazon.com as a shareholder in August, 2011, as a target group of social commerce service provider. we have gathered questionnaires from both service providers and the users from October 22, 2012 until October 31, 2012 to conduct an empirical analysis. We surveyed 160 service providers of Ticket Monster We also surveyed 160 social commerce users who have experienced in using Ticket Monster service. Out of 320 surveys, 20 questionaries which were unfit or undependable were discarded. Consequently the remaining 300(service provider 150, user 150)were used for this empirical study. The statistics were analyzed using SPSS 12.0. Implications of the empirical analysis result of this study are as follows: First of all, There are order differences in the importance of social commerce CSF between two groups. While service providers regard Price Economic as the most important CSF influencing purchasing intention, the users regard 'Trust' as the most important CSF influencing purchasing intention. This means that the service providers have to utilize the unique strong point of social commerce which make the customers be trusted rathe than just focusing on selling product at a discounted price. It means that service Providers need to enhance effective communication skills by using SNS and play a vital role as a trusted adviser who provides curation services and explains the value of products through information filtering. Also, they need to pay attention to preventing consumer damages from deceptive and false advertising. service providers have to create the detailed reward system in case of a consumer damages caused by above problems. It can make strong ties with customers. Second, both service providers and users tend to consider that social commerce CSF influencing purchasing intention are Price Economic, Utility, Trust, and Word of Mouth Effect. Accordingly, it can be learned that users are expecting the benefit from the aspect of prices and economy when using social commerce, and service providers should be able to suggest the individualized discount benefit through diverse methods using social network service. Looking into it from the aspect of usefulness, service providers are required to get users to be cognizant of time-saving, efficiency, and convenience when they are using social commerce. Therefore, it is necessary to increase the usefulness of social commerce through the introduction of a new management strategy, such as intensification of search engine of the Website, facilitation in payment through shopping basket, and package distribution. Trust, as mentioned before, is the most important variable in consumers' mind, so it should definitely be managed for sustainable management. If the trust in social commerce should fall due to consumers' damage case due to false and puffery advertising forgeries, it could have a negative influence on the image of the social commerce industry in general. Instead of advertising with famous celebrities and using a bombastic amount of money on marketing expenses, the social commerce industry should be able to use the word of mouth effect between users by making use of the social network service, the major marketing method of initial social commerce. The word of mouth effect occurring from consumers' spontaneous self-marketer's duty performance can bring not only reduction effect in advertising cost to a service provider but it can also prepare the basis of discounted price suggestion to consumers; in this context, the word of mouth effect should be managed as the CSF of social commerce. Third, Trade safety was not derived as one of the CSF. Recently, with e-commerce like social commerce and Internet shopping increasing in a variety of methods, the importance of trade safety on the Internet also increases, but in this study result, trade safety wasn't evaluated as CSF of social commerce by both groups. This study judges that it's because both service provider groups and user group are perceiving that there is a reliable PG(Payment Gateway) which acts for e-payment of Internet transaction. Accordingly, it is understood that both two groups feel that social commerce can have a corporate identity by website and differentiation in products and services in sales, but don't feel a big difference by business in case of e-payment system. In other words, trade safety should be perceived as natural, basic universal service. Fourth, it's necessary that service providers should intensify the communication with users by making use of social network service which is the major marketing method of social commerce and should be able to use the word of mouth effect between users. The word of mouth effect occurring from consumers' spontaneous self- marketer's duty performance can bring not only reduction effect in advertising cost to a service provider but it can also prepare the basis of discounted price suggestion to consumers. in this context, it is judged that the word of mouth effect should be managed as CSF of social commerce. In this paper, the characteristics of social commerce are limited as five independent variables, however, if an additional study is proceeded with more various independent variables, more in-depth study results will be derived. In addition, this research targets social commerce service providers and the users, however, in the consideration of the fact that social commerce is a two-sided market, drawing CSF through an analysis of perception gap between social commerce service providers and its advertisement clients would be worth to be dealt with in a follow-up study.

• Journal of the Korea Institute of Building Construction
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• v.15 no.4
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• pp.425-431
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• 2015

Since the construction of Kori 1 was completed in 1978, the construction projects for nuclear power plant are increasingly expanded into domestic and foreign sites. However, some of construction sites of nuclear power plant have the problems of process delay and cost loss due to lack of ability of risk management. The construction of reactor containment building in nuclear power plant is especially dotted with many risk factors because it needs professional skills and large-scale resources due to long duration compared with different construction phase. Therefore, it needs the study that analyzes risk factors expected in construction of reactor containment building and suggests way of stable performance of projects. So, this study assesses risk factors of construction of reactor containment building. For the objectives, this study uses survey for group of minority specialists of 36 experts. The risks of 24 factors is classified by criterions of process, cost, safety, and quality and the results of assessment is analyzed by analytic hierarchy process. As the results, the importance and priority of risk factors classified by each criterion were calculated and the applicability of analytic hierarchy process was identified to analyze risk factors of nuclear power plant construction. These will be baseline data for risk management in construction phase of reactor containment building.

• Journal of Korean Society of Forest Science
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• v.95 no.1
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• pp.73-81
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• 2006

This study has the object of deriving schemes for not only securing safety of chestnuts, which is the most important forest product in terms of both production and exportation, to consumers with implementing persistent production of them in harmony with the environment, but also producing environmentally friendly chestnuts that can contribute to the increase of a farm household's income through price differentiation from other chestnuts, which are grown by generally accepted ways. In order to do this, I performed an analysis of the reality and outcome from the management of farm households that produce environmentally friendly chestnuts. The result of the analysis demonstrated some problems such as poor establishment of farming skills in a beginning stage, administrative problems with weeding operations and prevention of blight, difficulty in ensuring distribution channels and high production cost. Therefore, propelling productive expansion of environmentally friendly chestnuts after resolving these problems requires many supports and ideas: establishment and diffusion of farming skill system under the cooperation of civil and government organizations, construction of environmentally friendly INM (Integrated Nutrient Management) and IPM (Integrated Pest Management), creation of production areas for improving productivity, introduction of 'Institution of Income Conservation for Environmentally-Friendly Production' that can help farmers to preserve integrity of income on their switchover to production of environmentally friendly chestnuts from generally-grown chestnuts, and finally strong and persistent promotion of environmentally friendly chestnuts towards existing farmers and consumers.

• Korean Journal of Construction Engineering and Management
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• v.20 no.3
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• pp.46-53
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• 2019

Recently, the need for emergency medical facilities is increasing due to a large-scale disaster. The Ministry of the Interior and Safety has completed the development of Disaster Resource Sharing System (DRSS). In this system, only air tent and negative pressure tent, which are classified and managed as equipment are resources related to emergency medical facility at disaster site. However, the characteristics of resources for the facility such as the time of input, a period of stay, transportation, and installation methods were not reflected. So, The purpose of this study is to propose improvements of management of resources for emergency medical facility at disaster site, that classified to materials and equipment in DRSS. This study analyzed the state of resources for facilities and the attributes of resources based on literature and disaster medical consultation of mobile hospitals. The resources for emergency medical facility are required to be linked to medical support resources and reflected in the DRSS, since emergency medical facility resources at the disaster site should be managed through a combination of medical resources classified as equipment. And future research on installation of emergency medical facilities plan considering the cost of the disaster management resources should be carried out.

• Korean Journal of Construction Engineering and Management
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• v.21 no.6
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• pp.46-55
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• 2020

The maintenance cost for highway pavement is gradually increasing due to the continuous increase in road extension as well as increase in the number of old routes that have passed the public period. As a result, there is a need for a method of minimizing costs through preventative grievance Preventive maintenance requires the establishment of a strategic plan through accurate prediction old Highway pavement. herefore, in this study, the XGBoost among machine learning classification-based models was used to develop a highway pavement damage prediction model. First, we solved the imbalanced data issue through data sampling, then developed a predictive model using the XGBoost. This predictive model was evaluated through performance indicators such as accuracy and F1 score. As a result, the over-sampling method showed the best performance result. On the other hand, the main variables affecting road damage were calculated in the order of the number of years of service, ESAL, and the number of days below the minimum temperature -2 degrees Celsius. If the performance of the prediction model is improved through more data accumulation and detailed data pre-processing in the future, it is expected that more accurate prediction of maintenance-required sections will be possible. In addition, it is expected to be used as important basic information for estimating the highway pavement maintenance budget in the future.

• Korean Journal of Construction Engineering and Management
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• v.6 no.4 s.26
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• pp.142-151
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• 2005

Several advanced countries have been continually developed PHC pile cutting automation machines for improving productivity, safety and quality of the conventional PHC pile cutting work. However, the target work of the previously developed PHC pile cutting automation machines is only crushing the head of PHC pile. Dangerous grinding work is still performed by workers with seven inch hand grinder. In domestic construction industry, the PHC pile cutting work is usually performed by a crusher and three to four skilled workers. Recent analysis results of the PHC pile cutting work reveal that it frequently makes a lot of cracks which significantly reduce the strength of the pile and is labor-intensive work. The primary objective of this study is to propose the end-effector which can effectively break PHC pile without any longitudinal cracks and to develop an automated pile cutting machine having unified grinder and crusher parts through a wide variety of laboratory and field tests. It is anticipated that the development of the automated pile cutting machine would be able to bring improvements in safety, productivity, quality as well as cost saving.

• Korean Journal of Construction Engineering and Management
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• v.10 no.1
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• pp.114-125
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• 2009

In this study, a design value analysis technique that considered stochastic LCC and stochastic performance evaluation was proposed, and by introducing the concept of reliability analysis, a decision making that secured reliability was supported. The results of this study, which was carried out according to the above objectives and methods, are summarized as follows: 1) The design value analysis procedures and value state function, improved in order to carry out a reliable analysis when evaluating alternate proposals that were extracted after the function definition was complete, were formalized, and in order to secure consistency and efficiency for value evaluation procedures, an evaluation index scheme was proposed; 2) Database collection and analysis were done for a bridge's LCC analysis. As for the collection scope of data, literature of previous research done on a bridge's LCC analysis was used as the basis for analysis, and for securing reliability regarding analysis results and dealing with uncertainty of collected data, the MCS technique was applied; 3) Weights and evaluation ranks for performance evaluation of each of the alternate proposals, as well as LCC analysis model, analysis period, discount rate, user expense, safety inspection and safety diagnosis expense conditions for LCC analysis were proposed. Lastly, a feasibility study was done and conclusion was made about "OO grand bridge and connecting road construction work execution design" project centered on value analysis execution case.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.1
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• pp.133-141
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• 2016

Although construction of any new nuclear power projects had not been launched since mid-1970s until recently in the USA, many new nuclear power plants have been constructed in many countries with the support of their governments mainly as part of their national energy security and electric source diversification policies. For many reasons, the nuclear power industry seemed to reclaim their renaissance from the beginning of this century and the investment in the nuclear power projects draw positive concern from the private financial sector. But the global financial crisis in 2008 and subsequent economic slow-down together with tighter bank credit regulations caused commercial banks, the main source of financing, to lose appetite for investing in new nuclear power projects. But the nuclear power economics shows that the nuclear power is viable in terms of the environmental benefit and long-term average cost compared to other power generation sources. Also doubt about nuclear power safety was much mitigated due to technology development and reinforced safety-related tests and monitoring. Therefore, the prospect for nuclear power market expansion remains positive although there are comparatively big differences among different scenarios. After Korea Electric Power Corp. won the UAE nuclear power project in December of 2009, the competition in nuclear power markets is undergoing huge changes. Competitors backed by the support of their own governments are now entering the market with many aggressive and innovative financing packages to win bids of new nuclear power projects. This report analyzed the nuclear power market prospects, competitive edges of nuclear power, risk management measures, and financing challenges and recommends alternative solutions to promote competitive edges in winning bids of new nuclear power projects.