• Journal of the Architectural Institute of Korea Structure & Construction
• /
• v.36 no.2
• /
• pp.117-126
• /
• 2020

The main objective of this experimental study is to investigate shear strength of reinforced concrete beams according to longitudinal reinforcement ratio (ρ) and size effect. In order to find out the shear strength according to the tensile reinforcement ratio, in particular, the main variables are 100%, 75% and 50% of ρ=0.01 which is widely used in construction field. A total of twelve RC beams were tested under 4-point loading conditions. In addition to the existing proposal equations, the theoretical values such as KBC and ACI equations are compared with the experimental data. Through this analysis, this study is designed to provide more reasonable equations for shear design of reinforced concrete beams. When shear reinforcement bar spacing of nine specimens (R^*-1, R^*-2, and R^*-3 series) fixed as d/s=2.0 and three specimens of R^*-4 series fixed as d/s=1.5 are compared, the shear strength of two groups showed similar values. As a result, the current standard of d/s=2.0 for shear reinforcement bar spacing may be somewhat alleviated.

• Journal of the Architectural Institute of Korea Structure & Construction
• /
• v.35 no.12
• /
• pp.181-188
• /
• 2019

The maintenance of school building is pivotal issue. However, it is difficult to obtain basic analysis data for LCC(Lifecycle Cost) analysis and maintenance planning of school building. Therefore, this study proposed System Dynamics(SD) techniques to make maintenance decisions for school building. The interaction between the major parameters related to the aging of a building, maintenance activities, and cost were expressed in Causal Loop Diagram. Based on this, the formula for the relationship between causal maps was defined and converted to Stock and Flow Diagram. Through the completed SD model the 50-year plan of 214 educational building were tested by considered in account budget, maintainability, and budget allocation opinions. As a result, the integrated SD model demonstrated that it can support strategic decision making by identifying the status class and LCC behavior of school buildings by scenario. According to the scenario analysis, the rehabilitation action of preventive maintenance that primarily repairs the buildings in condition grade C showed the best performance improvement effect relative to the cost. Therefore, if the proposed SD model is expanded to consider the effects of other educational policies, the crucial performance improvement budget can be estimated in the long-term perspective.

• Journal of Forest and Environmental Science
• /
• v.36 no.4
• /
• pp.318-325
• /
• 2020

This study was carried out to find the effects of aromatherapy using natural fragrance on reducing stress and improving job satisfaction of transportation workers in the taxi industry. A total of 120 workers were divided into the experimental group and the control group according to the inhalation of the fragrance and tested for 2 weeks. After 2 weeks, the difference of emotional change, stress analysis, and evaluation of job satisfaction according to aromatherapy were compared between the two groups. The result showed that the experimental group had a higher interest in scent products than the control group and that they wanted to encounter a lot of real scents, indicating that aromatherapy caused positive interest in general scent likability. In addition, the experimental group said that the inhalation of fragrance would refresh the feeling of the passengers in the vehicle and smoothly communicate with the passengers. Especially, it showed a significant difference between the two groups in terms of tension relief, pleasure and good mood by inhalation of fragrance, indicating the positive effect on job satisfaction.

• The Journal of Asian Finance, Economics and Business
• /
• v.8 no.3
• /
• pp.1275-1286
• /
• 2021

The purpose of this study is to employ the theory of consumption value and consumers' innovative personality characteristics to explain the adoption of new personal electronics devices in Vietnamese market. This study adapts a quantitative survey-based approach to test hypotheses about relationship between consumption value, product specific innovativeness and new product adoption. The study uses a quantitative data set of 915 consumers who owned one mobile electronic device at least in Ho Chi Minh city, one of the biggest cities of Vietnam. The data was collected through personal interview and convenient sampling method. The conceptual model was tested using PLS structural equation model. The findings of this study suggest that both consumption value and product specific innovativeness influence the adoption of new electronic products. The results also reveal that product specific innovativeness mediates the relationship between consumption value and new product adoption. The study further identified that consumption value was taken as a second-order multidimensions construct with five components, namely functional value, epistemic value, economic value, social value and emotional value. As a result, the research suggests some implications to enhance marketers' capabilities to develop strategies for launching new hi-tech products in an emerging market as Vietnam.

• Korea Trade Review
• /
• v.44 no.3
• /
• pp.25-42
• /
• 2019

This research examined the mediation effect of Workforce Agility (WA) on the relationship between environmental uncertainty and operational performance. We manipulated the control variables that are known to be affected by employment flexibility. Employment flexibility is caused by idiosyncratic characteristics of Korean port system. The analysis was tested by Baron & Kenny's method. The result indicates that each path of the proposed model is significant. Furthermore, the mediation effect was checked with the Sobel Test. The research revealed that environment uncertainty poses an indirect effect on operational performance. Both supply/demand uncertainty and technological uncertainty affected operational performance through the mediation effect of WA. Most of the distribution centers located in Busan Newport Distripark are operated in a bimodal labor (human resource) system which includes both permanent employees (workers) and temporary employees (workers). This empirical research provides theoretical and managerial implications by suggesting ways to increase efficiency in distribution center operation through WA enhancement, and to improve the unloading labor system.

• Computers and Concrete
• /
• v.26 no.6
• /
• pp.587-593
• /
• 2020

In this study, bond behavior of ordinary concrete and rebars with different diameters and development length was investigated by using Hinged Beam Test (HBT) and Eccentric Pull-Out Test (EPT) comparatively. For this purpose, three different rebar size and development length depending on rebar diameter were chosen as variables. Three specimens were produced for each series of specimens and totally 54 specimens were tested. At the end of the tests it was observed that obtained results for both tests were quite similar. On the other hand, increased bar size, especially for the specimen with 14 mm bar size and 14 development length (lb), caused shear failure of test specimens. This situation infers that when bigger bar size and lb are used in such test, dimensions of test specimens should be chosen bigger and stirrups should be used for producing of test specimens to obtain more adequate result by preventing shear failure. Also, a nonlinear regression analysis was employed between HBT and EPT results. There was a high correlation between the EPT values, lb, rebar diameters and estimated theoretical HBT. In addition, at the end of the study an equation was suggested to estimate bond strength for HBT by using EPT results.

• Journal of Korea Game Society
• /
• v.20 no.6
• /
• pp.23-30
• /
• 2020

There are many cases in the game. So, Game have to learn a lot. This paper uses reinforcement learning to improve the learning speed. However, because reinforcement learning has many cases, it slows down early in learning. So, the speed of learning was improved by using the minimax algorithm. In order to compare the improved performance, a Gonu game was produced and tested. As for the experimental results, the win rate was high, but the result of a tie occurred. The game tree was further explored using progressive deepening to reduce tie cases and win rate has improved by about 75%.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.12
• /
• pp.4909-4926
• /
• 2020

Cyberattacks penetrate the server and perform various malicious acts such as stealing confidential information, destroying systems, and exposing personal information. To achieve this, attackers perform various malicious actions by infecting endpoints and accessing the internal network. However, the current countermeasures are only anti-viruses that operate in a signature or pattern manner, allowing initial unknown attacks. Endpoint Detection and Response (EDR) technology is focused on providing visibility, and strong countermeasures are lacking. If you fail to respond to the initial attack, it is difficult to respond additionally because malicious behavior like Advanced Persistent Threat (APT) attack does not occur immediately, but occurs over a long period of time. In this paper, we propose a technique that detects an unknown attack using an event log without prior knowledge, although the initial response failed with anti-virus. The proposed technology uses a combination of AutoEncoder and 1D CNN (1-Dimention Convolutional Neural Network) based on semi-supervised learning. The experiment trained a dataset collected over a month in a real-world commercial endpoint environment, and tested the data collected over the next month. As a result of the experiment, 37 unknown attacks were detected in the event log collected for one month in the actual commercial endpoint environment, and 26 of them were verified as malicious through VirusTotal (VT). In the future, it is expected that the proposed model will be applied to EDR technology to form a secure endpoint environment and reduce time and labor costs to effectively detect unknown attacks.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.21 no.3
• /
• pp.73-79
• /
• 2021

In the wave of the 4th industrial revolution, smart factory is required in many factories. However, small and mid-sized companies (SMEs) still have aging machines and are having difficulties in the data collection stage, which is the basis of smart factories. This study proposes a low cost monitoring method by using an open source based technology that extracts data from the image of the facility control panel without the need for modification of existing facilities. The proposed method was tested and evaluated for forging facilities in automobile parts manufacturing plants through prototyping. As a result of the evaluation, it was confirmed that low-cost facility monitoring is possible, and it will help SMEs build smart factories.

• Journal of Information Processing Systems
• /
• v.17 no.3
• /
• pp.645-657
• /
• 2021

Along with the rapid development of the economy, the urban scale has extended rapidly, leading to the formation of different types of urban function districts (UFDs), such as central business, residential and industrial districts. Recognizing the spatial distributions of these districts is of great significance to manage the evolving role of urban planning and further help in developing reliable urban planning programs. In this paper, we propose an automatic UFD division method based on big data analysis of point of interest (POI) data. Considering that the distribution of POI data is unbalanced in a geographic space, a dichotomy-based data retrieval method was used to improve the efficiency of the data crawling process. Further, a POI spatial feature analysis method based on the mean shift algorithm is proposed, where data points with similar attributive characteristics are clustered to form the function districts. The proposed method was thoroughly tested in an actual urban case scenario and the results show its superior performance. Further, the suitability of fit to practical situations reaches 88.4%, demonstrating a reasonable UFD division result.