• Safety and Health at Work
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• v.9 no.1
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• pp.10-16
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• 2018

Background: A detailed evaluation of the underground mine climate requires extensive measurements to be performed coupled to climatic modeling work. This can be labor-intensive and time-consuming, and consequently impractical for daily work comfort assessments. Therefore, a simple indicator like a heat stress index is needed to enable a quick, valid, and acceptable evaluation of underground climatic conditions on a regular basis. This can be explained by the unending quest to develop a "universal index," which has led to the proliferation of many proposed heat stress indices. Methods: The aim of this research study is to discuss the challenges in identifying and selecting an appropriate heat stress index for thermal planning and management purposes in underground mines. A method is proposed coupled to a defined strategy for selecting and recommending heat stress indices to be used in underground metal mines in the United States and worldwide based on a thermal comfort model. Results: The performance of current heat stress indices used in underground mines varies based on the climatic conditions and the level of activities. Therefore, carefully selecting or establishing an appropriate heat stress index is of paramount importance to ensure the safety, health, and increasing productivity of the underground workers. Conclusion: This method presents an important tool to assess and select the most appropriate index for certain climatic conditions to protect the underground workers from heat-related illnesses. Although complex, the method presents results that are easy to interpret and understand than any of the currently available evaluation methods.

• Structural Monitoring and Maintenance
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• v.11 no.2
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• pp.127-148
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• 2024

Estimating cable tension is important in the maintenance of cable structures, such as cable-stayed bridges. In practice, the higher-order vibration method based on natural frequencies is used. In recent years, dampers have been installed onto cables to suppress aerodynamic vibration. Because the higher-order vibration method is suitable to cables without a damper, the damper must be removed before using this method. Because damper removal is time-consuming and labor-intensive, a previous study proposed a tension estimation method for a cable with a damper based on the natural frequencies, which does not require the damper's removal. However, the previous method relies on the modeling accuracy of the damper's complex stiffness. The damper design formula, while intended for design purposes, does not consistently reflect the damper's actual complex stiffness. Therefore, the estimation accuracy deteriorates when the damper's actual complex stiffness deviates from the damper design formula. With this background, this paper introduces a novel tension estimation method based on mode shapes, which circumvents damper modeling errors since mode shapes are independent of the damper's complex stiffness. In the numerical verification using 90 models, the proposed method estimated tension accurately with an estimation error within 0.59%. In the experimental verification, the proposed method estimated tension accurately with an estimation error within 4.17% except for one case, while the previous method had an estimation error of 44% when the damper design formula was used. The proposed method was found to be superior to the previous method in terms of accuracy and practicality by numerical simulation and experiment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.236-242
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• 2019

Recently, scanning projects have been carried out in various construction and construction fields for maintenance purposes. The point cloud generated by the scan results is composed of a number of points representing the object to be scanned. The process of extracting the necessary information, including dimensions, from such scan data is called paradox. The reverse engineering process of modeling a point cloud as BIM involves considerable manual work. Owing to the time-consuming reverse engineering nature of the work, the costs increase exponentially when rework requests are made, such as design changes. Reverse engineering automation technology can help improve these problems. On the other hand, the reverse design product is variable depending on the use, and the kind and detail level of the product may be different. This paper proposes the G2BM (Geometry-to-BIM mapping) rule definition method that automatically maps a BIM object from a primitive geometry to a BIM object. G2BM proposes a process definition and a customization method for reverse engineering BIM objects that consider the use case variability.

• Korean Institute of Interior Design Journal
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• v.19 no.3
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• pp.196-204
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• 2010

Human beings are having suffered from the unexpected climate changes which are caused by global warming leaded from air pollution. More than 3 billions of people will be forced to experience insufficient water in 2015. In Korea, over 70% of precipitation has been concentrating in Summer season. Furthermore, natural disasters has been occurred constantly all over the country. The unusual flood and drought have broken out not only victims but also, property damages. By the natural condition, the effective consuming and controlling system of water is going to be the core business field and constructing dams will be encouraged and promoted for the system. To convince the objectionable against the constructing dams, a dam exhibition center stands the very important position by being responsible for the presenting positive factors and highlighting the beneficial functions. The dam exhibition center is built as complex space combined by information center regarding water resources and visitor center for the community nearby the inundated area. Combined of the different purposes, the dam exhibition center can be confused to understand the concept and contents established in the space. To enhance the visitors' understanding contents of the dam exhibition center, the spatial composition and contents are being analyzed with existing centers and define the most effective exhibition methods between the spaces and visitors. This study will be the basic quantitative analysis data for the following design works those can get the better insight how to make visitors to get information and agreement of constructing dams effectively.

• The Transactions of the Korea Information Processing Society
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• v.13 no.3
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• pp.122-129
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• 2024

Though programming education has been stressed recently, the elementary, middle, and high school students are having trouble in programming education. Most programming environments for them are based on block coding, which hinders them from moving to text coding. The traditional PC environment has also troubles such as maintenance problems. In this situation, mobile applications can be considered as alternative programming environments. This paper addresses the design and implementation of coding applications for mobile devices. As a prototype, a Scheme interpreter mobile app is proposed, where Scheme is used for programming courses at MIT since it supports multi-paradigm programming. The implementation has the advantage of not consuming the network bandwidth since it is designed as a standalone application. According to the benchmark result, the execution time on Android devices, relative to that on a desktop, was 131% for the Derivative and 157% for the Tak. Further, the maximum execution times for the benchmark programs on the Android device were 19.8ms for the Derivative and 131.15ms for the Tak benchmark. This confirms that when selecting an Android device for programming education purposes, there are no significant constraints for training.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.4
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• pp.105-112
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• 2022

Recently, many studies using reinforcement learning-based autoscaling have been performed to make autoscaling policies that are adaptive to changes in the environment and meet specific purposes. However, training the reinforcement learning-based Horizontal Pod Autoscaler(HPA) policy in a real environment requires a lot of money and time. And it is not practical to retrain the reinforcement learning-based HPA policy from scratch every time in a real environment. In this paper, we implement a reinforcement learning-based HPA in Kubernetes, and propose a transfer leanring technique using a queuing model-based simulation to accelerate the training of a reinforcement learning-based HPA policy. Pre-training using simulation enabled training the policy through simulation experience without consuming time and resources in the real environment, and by using the transfer learning technique, the cost was reduced by about 42.6% compared to the case without transfer learning technique.

• Journal of Korean Society of Forest Science
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• v.65 no.1
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• pp.80-91
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• 1984

The purposes of this study are to analyze and forecast the domestic demand for papers by regression models with time-series data (1965-81). For the period of 1965-81, the real GNP of Korea grew at annual average increase rate of 8.8 percent. On the other hand, the domestic demand of papers grew at annual average increase rate of 17.9 percent in this period. Especially, the annual average increase rate for board-papers accounted to 25.8 percent. To analyze domestic demand for papers, GNP, per capita GNP, price findex of papers, production activity index of the major papers consuming industries and price index of substitutive goods were selected as independent variables. The expected values of domestic demand for papers were computed by forecasting equations as follows. T-values are in parentheses. ${\ell}nDDP=2.452+1.986{\ell}nPG-0.844{\ell}nPWI$ $(33.397)^*\;(-6.149)^*\;R^2=0.997$ ${\ell}nDDP=6.468+0.827{\ell}nPDA$ $(17.403)^*\;R^2=0.950$ DDP : Domestic demand for papers PG : Real GNP per capita (1,000 won) PWI : Real price index of papers (1980 = 100) PDAV : Production activity index of the major papers consuming industries The results analyzed and forecasted by these models are summarized as follows: The domestic demand for papers had positive correlation toward per capita GNP and production activity index of the major papers consuming industries. Per capita GNP elasticity of the domestic demand for papers was the most elastic among independent variables. The price elasticity of domestic demand for papers had negative sign and inelastic. These were not only statistically significant but theoretically compatible. The domestic demand for papers was projected to be 3,152-4,470 thousand mit in 1991, representing at annual increase rate of 5.0-12.4 percent during the period of 1982-91. Domestic demand for papers per capita was projected to be 69.1-98.0 kg in 1991.

• Korean Journal of Community Nutrition
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• v.12 no.3
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• pp.344-351
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• 2007

The purposes of this study were to analyze the consumer inclination to convenience towards HMR in order to verify the structural correlation of the actual state of consumption, and to analyze consequently, the direct or indirect effects among 'frequency of using,' 'preference', 'satisfaction', and 'intention to repurchase'. The subjects were adults in their twenties or older who had used HMRs and lived in Seoul and Gyeonggi Province in Korea. Random sampling of 550 subjects, who were distributed a questionnaire from March 12 to 30, 2005. A total of 451 questionnaires were returned (the return rates were 82%). The main results of this study were as follows : Regarding the types of HMR, 'Ready to eat' had higher preference (3.31), satisfaction (3.33) and 'intention to purchase it again' (3.38) than those of 'Ready to heat' and 'Ready to end-cook.' Consumer inclination to convenience towards HMR was analyzed in order to verify the structural correlation of the actual state of consumption, and consequently, the direct or indirect effects among 'frequency of using,' 'preference', 'satisfaction', and 'intention to repurchase' were analyzed. The gross effect of 'frequency of using' on 'intention to repurchase' was 0.435, the gross effect of preference on 'intention to purchase it again' was 0.659, and the gross effect of satisfaction on 'intention to purchase it again' was 0.772 for 'Ready to eat.' The gross effect of 'frequency of using' on 'intention to repurchase' was 0.448, the gross effect of preference on 'intention to repurchase' was 0.556, and the gross effect of satisfaction on 'intention to repurchase' was 0.654 for 'Ready to heat.' The gross effect of 'frequency of using' on 'intention to repurchase' was 0.432, the gross effect of preference on 'intention to repurchase' was 0.494, and the gross effect of satisfaction on 'intention to repurchase' was 0.608 for 'Ready to end-cook.' To summerize the above results, there was a difference of the structural correlation among component concepts of the actual state of consuming according to the criteria of HMR. Thus, it implied that differentiated sales strategies were needed according to the criteria of HMR.

• Steel and Composite Structures
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• v.48 no.2
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• pp.163-177
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• 2023

Complex and intricate preparation techniques, the imperative for utmost precision and sensitivity in instrumentation, premature sample failure, and fragile specimens collectively contribute to the arduous task of measuring the fracture toughness of concrete in the laboratory. The objective of this research is to introduce and refine an equation based on the gene expression programming (GEP) method to calculate the fracture toughness of reinforced concrete, thereby minimizing the need for costly and time-consuming laboratory experiments. To accomplish this, various types of reinforced concrete, each incorporating distinct ratios of fibers and additives, were subjected to diverse loading angles relative to the initial crack (α) in order to ascertain the effective fracture toughness (Keff) of 660 samples utilizing the central straight notched Brazilian disc (CSNBD) test. Within the datasets, six pivotal input factors influencing the Keff of concrete, namely sample type (ST), diameter (D), thickness (t), length (L), force (F), and α, were taken into account. The ST and α parameters represent crucial inputs in the model presented in this study, marking the first instance that their influence has been examined via the CSNBD test. Of the 660 datasets, 460 were utilized for training purposes, while 100 each were allotted for testing and validation of the model. The GEP model was fine-tuned based on the training datasets, and its efficacy was evaluated using the separate test and validation datasets. In subsequent stages, the GEP model was optimized, yielding the most robust models. Ultimately, an equation was derived by averaging the most exemplary models, providing a means to predict the Keff parameter. This averaged equation exhibited exceptional proficiency in predicting the Keff of concrete. The significance of this work lies in the possibility of obtaining the Keff parameter without investing copious amounts of time and resources into the CSNBD test, simply by inputting the relevant parameters into the equation derived for diverse samples of reinforced concrete subject to varied loading angles.

• The Korean Journal of Franchise Management
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• v.13 no.1
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• pp.47-57
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• 2022

Purpose: Recently, it is common to see cases where an amount similar to the cost of a meal is spent on dessert, or an amount greater than the cost of a meal is spent on dessert. The generation MZ is showing a tendency of 'value consumption' by consuming values and beliefs in consideration of the recent impact on society and the environment. Therefore, this study aims to analyze the effect of dessert cafe quality and eco-friendly behavior on customer trust and loyalty targeting the generation MZ who have visited desert cafés. This study examined the mediating role of customer trust in the relationships between desert café quality, eco-friendly behavior and customer loyalty, and also the moderating effect of and eco-friendly behavior on customer trust and customer loyalty. Research design, data, and methodology: To achieve purposes of this study, 229 data were collected from respondents who visited desert café and analyzed using measurement model (reliability test and correlation analysis), Fornell-Larcker Criterion and Heterotrait-Monotrait Ratio (HTMT) assessment, and structural equation model (PLS-SEM) with SPSS 22.0 and SmartPLS 3.3.7. Results: The research results are as follows. First, desert cafes' quality positively influenced customer trust but did not customer loyalty. Second, desert cafes' eco-friendly behavior positively influenced customer trust and customer loyalty. Fourth, the interaction term of dessert cafe quality and eco-friendly behavior did not influence customer trust and customer loyalty. Conclusions: This study emphasized the necessity of service quality and eco-friendly behavior of dessert cafes by examining the relationship between the quality of dessert cafes and eco-friendly behaviors, customer trust and loyalty. It also found the importance of the role of trust in securing loyal customers. In order to secure and retain loyal customers, the owners of dessert cafes should make effortsto improve the quality of the cafes' products and services so that customers can feel a sense of trust, and actively publicize that they are practicing eco-friendly management. As a result of this study, it is intended to provide practical implications for the management of dessert cafes by understand ing the effects of product and service quality and eco-friendly behaviors of companies to bakery industry workers and start-ups.