• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.43 no.5
• /
• pp.601-610
• /
• 2023

The comprehension of water-level behavior in rivers is essential for effective flood and river environmental management. The objective of this study is to propose a methodology that can be used by field engineers engaged in actual practice, to readily identify the characteristics of water-level behavior during flood events. To this end, a total of 45 historical water-level records from 2010 to 2022 year, which provide flood information for the flood vulnerable districts of the Han River, were obtained. A Water-level Rise Behavior Curve (WRBC) was developed and suggested to quantify the amount of water-level rise per unit time during flood. As a result, the water-level rises by more than 80% of the total rise within the first 6.2 hours, followed by a gradual rise. The time required to achieve a particular equilibrium varied depending on the area and runoff characteristics of the upstream. Furthermore, the study revealed that the WRBC provides a statistical representation of the water-level rise trend during floods, and can be effectively utilized for flood mitigation measures in waterfront spaces and irrigation facilities.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.51 no.1
• /
• pp.1-12
• /
• 2023

The ongoing Yongsan Park development project began in 1988 with the development of a utilization plan for the US Army base in Yongsan after the Army relocation. This study aimed to draw implications for the Yongsan Park project by focusing on Yongsan Family Park. Among the public records of Yongsan Park and Yongsan Family Park transferred to the Seoul Metropolitan Archives, 53 major records were analyzed. The results are as follows. First, Yongsan Family Park, built on the site of the US Army golf course in 1992, was considered a part of the Yongsan Park plan and holds status as the first phase of the Yongsan Park project. Second, despite its status, Yongsan Family Park opened as a temporary park occupied by urban facilities. A design and detailed roadmap of the development process is necessary to make Yongsan Park more resilient. Third, organizing and systematizing public records is necessary because lessons learned through past park development processes can be applied to the current project. This study is meaningful since it uncovered important issues of urban planning discussed in the process of Yongsan Family Park development through a complete analysis of public records, examined the linkage between Yongsan Family Park, which was not known until now, and the ongoing Yongsan Park project, and reaffirmed the importance of park archiving for long-term development projects.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.51 no.1
• /
• pp.85-97
• /
• 2023

Seoul Boramae Park was opened on May 5, 1986, after the Republic of Korea Air Force Academy relocated to Cheongju City in 1985. This study aims to examine the birth and evolution of Seoul Boramae Park and diagnose the park's value being transformed from the former site of the Air Force Academy. Policy reports and newspaper data were analyzed as a research method, focusing on Seoul public records. The study results are as follows. First, Seoul Boramae Park is a large-scale park created before the policy for parks on relocated sites we enacted. Second, Seoul Boramae Park has historical value as an urban park where memories and traces of the Air Force Academy overlap. Third, Seou Boramae Park contributed to regional change by promoting the public value of parks created on the relocated sites with an urban planning method. Seoul Boramae Park has implications for Korean landscape history as a case of securing large green areas in Seoul and presenting its function and roles as a park created on a relocated site.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.25 no.2
• /
• pp.141-155
• /
• 2023

Monitoring technology based on electrical resistivity is widely used for non-destructive data collection and health analysis of underground structures and tunnels. Vulnerable sections such as fault zone generates many problems during construction of the tunnel. These problems cause displacement and stress changes of the ground. Therefore, it is necessary to predict the state of the fault zone section to ensure the mechanical stability of the underground structure. Monitoring the size of joints and the porosity of the fillings is essential for rocks. Previous studies have not considered the variety of fillings in rock joints. In this study, electrical resistivity tests were conducted according to the particle mixing state of the sandy fillings. When the size of fillings is decreased at the constant porosity, the electrical resistivity tends to increase. The results of this study are expected to be useful as basic electrical resistivity data for predicting the ground conditions and evaluation of the ground behavior that is containing sandy fillings in the rock joint for tunnels.

• Journal of the Institute of Convergence Signal Processing
• /
• v.23 no.4
• /
• pp.228-233
• /
• 2022

This study is an experimental study on how to use phase change materials(PCM) to generate electrical energy for long-term operation of underwater unmanned vehicles. The electrical energy generation method is a volume change and a pressure change that occur as a phase change material changes to a solid or liquid state according to temperature, and the change in pressure creates a flow of fluid to create electrical energy. Polyethylene glycol was used as a phase change material considering the temperature of the ocean. In addition, an electrical energy generating device that converts volume change into pressure at low temperature (1℃~2℃) in solid state and high temperature (21℃~25℃) in liquid state was fabricated. As a result of the experiment, the pressure change according to the phase change rapidly changed between 1 hour and 2 hours, and maintained a pressure of about 24MPa after 4 hours. Through this, it was confirmed that it can be used as a power source for underwater unmanned vehicles using phase change materials and temperature differences. In addition, it was found that a more improved design should be made in order to apply the phase change material to an underwater unmanned vehicle.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.18 no.2
• /
• pp.251-258
• /
• 2023

In this paper, we propose DLP(Dual Linear Polarization) stack antenna for private network. The proposed antenna has general stack structure and design airgap between two substrate to obtain the maximum gain. Also, to improve cross polarization isolation, two feeding port is designed to separate for each substrate. The size of each patch antenna is 17.80 mm(W1)×16.70 mm(L1) for lower patch and 18.56 mm(W2)×18.73 mm(L2) for upper patch, which is designed on the FR-4 substrate which thickness (h) is 1.6 mm, and the dielectric constant is 4.3, and which is 40.0 mm(W)×40.0 mm(L) for total size of substrate. From the fabrication and measurement results, bandwidths of 100 MHz (4.74 to 4.84 GHz) for feeding port 1, and 150 MHz (4.67 to 4.82 GHz) for feeding port 2 are obtained on the basis of -10 dB return loss and transmission coefficient S21 is got under the -20 dB. Also, cross polarization isolation between each feeding port obtained

• Journal of the Korean Society for information Management
• /
• v.40 no.1
• /
• pp.225-258
• /
• 2023

The purpose of this study is to investigate the current status and characteristics of research data sharing by domestic researchers by analyzing the data sharing mechanism and repository specified in DAS of papers authored by domestic researchers. To this end, in this study, papers of researchers belonging to domestic institutions published in PLOS ONE from 2014 to 2022 were selected as the subject of the study. First of all, the status of DAS's existence in the papers was identified, the types of data-sharing mechanisms were analyzed using precedent studies, and the trend of changes in each data-sharing mechanism over time was investigated. As a result, it was found that DAS was written in 99.6% of the target papers, and the types of data-sharing mechanisms were similar to international patterns, but preferred types were changing over time. Afterward, focusing on repositories among data sharing mechanisms, the number and ratio of repositories mentioned in DAS were identified, and the trend of changes in use of the five repositories mentioned a lot was analyzed in a time series. In addition, the presentation method, type, and validity of the data access point mentioned along with the repository were also investigated. It was confirmed that the top five frequently mentioned repositories account for 60% of all repository mentions, and the use of a repository dealing with data codes is increasing; in addition, it was found that most of the data access points presented with the repository were valid.

• The Journal of the Acoustical Society of Korea
• /
• v.42 no.2
• /
• pp.133-142
• /
• 2023

The office environment is changing according to work types, Information Technology (IT) advancements, and the Coronavirus disease (COVID)-19 situation. In order for office space users to perform their tasks comfortably and efficiently, it is necessary to secure individual privacy as well as easy communication among members. In Korea, the demand for improving the acoustic performance of office spaces is also increasing, but the related performance criteria and guidelines have not been established. In this study, standardization of office space acoustic performance measurement and evaluation methods and European countries' acoustic performance criteria were compared and reviewed. It is proposed to comprehensively review international standardization trends and acoustic performance standards in each country and to establish and utilize criteria for evaluating the acoustic performance and satisfaction of office spaces in Korea through our survey. Considering the international standardization direction and compatibility with communication and Public Address (PA) systems, it is appropriate to establish criteria using the speech transmission index or Speech Transmission Index (STI) application index. This criterion will be highly utilizable and compatible. In addition, since the office furniture industry is interested in improving the acoustic performance of office space, it is necessary to establish a labelling system for speech level reduction of office furniture.

• KIPS Transactions on Computer and Communication Systems
• /
• v.12 no.3
• /
• pp.119-126
• /
• 2023

Sarcopenia is not well known enough to be classified as a disease in 2021 in Korea, but it is recognized as a social problem in developed countries that have entered an aging society. The diagnosis of sarcopenia follows the international standard guidelines presented by the European Working Group for Sarcopenia in Older People (EWGSOP) and the d Asian Working Group for Sarcopenia (AWGS). Recently, it is recommended to evaluate muscle function by using physical performance evaluation, walking speed measurement, and standing test in addition to absolute muscle mass as a diagnostic method. As a representative method for measuring muscle mass, the body composition analysis method using DEXA has been formally implemented in clinical practice. In addition, various studies for measuring muscle mass using abdominal images of MRI or CT are being actively conducted. In this paper, we develop an AI image segmentation model based on abdominal images of CT with a relatively short imaging time for the diagnosis of sarcopenia and describe the multicenter validation. We developed an artificial intelligence model using U-Net that can automatically segment muscle, subcutaneous fat, and visceral fat by selecting the L3 region from the CT image. Also, to evaluate the performance of the model, internal verification was performed by calculating the intersection over union (IOU) of the partitioned area, and the results of external verification using data from other hospitals are shown. Based on the verification results, we tried to review and supplement the problems and solutions.

• Journal of the Korean Geotechnical Society
• /
• v.22 no.6
• /
• pp.41-49
• /
• 2006

This paper deals with development and dissipation of excess pore pressure induced by the cyclic load. Cyclic triaxial tests on reconstituted samples of weathered residual soils, which were widely used as construction materials in Korea, were performed. Test results showed that excess pore pressures developed under undrained condition increased with the increase of cyclic loads and confining pressures. And a new concept based on modified excess pore pressure ratio (MEPPR) was proposed for simply estimating excess pore pressures in terms of the number of cyclic load, irrespective of cyclic loads and confining pressures. Also, it was proposed that excess pore pressure ratio (EPPR) could be effectively utilized to estimate volumetric strains during dissipation which decreased as confining pressures increased. Consequently, concept and method to effectively estimate settlements under non-liquefied condition, induced by dynamic loads such as earthquake loads were evaluated based on laboratory test results for reconstituted weathered residual soils.