• The Journal of Information Systems
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• v.31 no.3
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• pp.47-65
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• 2022

Purpose With the recent development of Big Data and Artificial Intelligence technology, self-driving technology has developed into three stages (partial self-driving) or four stages (conditional self-driving), it is expected to bring a new paradigm to transportation in the city. Although many researchers are researching related technologies, there is no research on self-driving for disabled persons. In this study, the basic research was conducted based on the assumption that the shared self-driving car used by the disabled person is similar to the special transportation currently driving. Design In this study, data analysis and machine learning techniques were utilized to analyze the mobility patterns of disabled persons by type and to search for leading factors affecting the traffic volume of special transportation. Findings The study found that external physical disorders and developmental disorders often visit general welfare centers, internal organ disorders often visit general hospitals, and the elderly and mental disorders have various destinations. In addition, machine learning analysis showed that the main transportation routes for the disabled person use arterial roads and auxiliary arterial roads and that the ratio of building usage-related variables affecting the use of special transportation for a disabled person is high. In addition, the distance to the subway and bus stops was also mentioned as a meaningful variable. Based on these analysis results, it is expected that the necessary infrastructure for shared self-driving cars for disability person traffic will be used as meaningful research data in the future.

• Journal of Korean Medicine for Obesity Research
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• v.22 no.2
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• pp.115-124
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• 2022

Objectives: In this study, we investigated physicochemical characteristics and antioxidant activity of Artemisia argyi H. fermented with lactic acid bacteria. Methods: The A. argyi water extract was fermented using lactic acid bacteria isolated from kimchi at 30℃ for 96 h. To evaluate the physicochemical characteristics, we investigated pH, total acidity, viable cells, free sugars, free organic acids, and free amino acids contents during fermentation. In addition, we examined antioxidant activity of fermented Artemisia argyi H. by measurement of 2,2-diphenyl-1-(2,4,6-trinitrophenyl)-hydrazinyl (DPPH) and 2,2'-azubi-bus-3-ethylbenzothiazoline-6-sulfonic acid (ABTS⁺) scavenging activities. Results: During fermentation time, pH of fermented A. argyi was decreased from 4.57 to 3.22, and total acidity was increased from 0.39% to 1.63%. The number of lactic acid bacteria fermented A. argyi was increased from 1.28×10⁷ CFU/ml to 3.75×10⁸ CFU/ml during fermentation time. The free sugars of fermented A. argyi were confirmed glucose and sucrose. In addition, the organic acid content of fermented A. argyi was the highest in oxalic acid and lactic acid. In the composition of free amino acids, content of ornithine increased from 4.4 mg/100 g to 18.8 mg/100 g compared with non-fermented A. argyi. Furthermore, DPPH and ABTS⁺ radical scavenging activities of fermented A. argyi increased in a dose-dependent manner. Conclusions: In conclusion, our data suggest that lactic acid fermentation of A. argyi could be used as a functional food for antioxidants.

• Land and Housing Review
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• v.14 no.3
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• pp.77-92
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• 2023

The aim of the study is to analyze urban characteristics that affect carbon emissions of buildings. The analysis was conducted at the level of 424 administrative districts in Seoul. The main variables used in the analysis were energy consumption and carbon emissions of buildings published in the Seoul Metropolitan Government's energy information platform 2021. It was found that carbon emissions per unit building were high in Jongno, Gangnam, Guro, and Mok-dong. A regression analysis using the spatial lag model (SLM) identifies that the variables that affect the carbon emissions of buildings were; commercial, educational, business and industrial facility variables as built environment factor; number of residents; traffic volume, number of bus routes and number of subway stations as transportation facilities factors; and environmental factors such as green area and river area.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.1
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• pp.219-232
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• 2023

Mobility services need to change according to the regional characteristics of the target service area. Accordingly, analysis of mobility patterns and characteristics based on Origin-Destination (OD) data that reflect travel behaviors in the target service area is required. However, since conventional methods construct the OD data obtained from the administrative district-based zone system, it is hard to ensure spatial homogeneity. Hence, there are limitations in analyzing the inherent travel patterns of each mobility service, particularly for new mobility service like Demand Responsive Transit (DRT). Unlike the conventional approach, this study applies a data-driven clustering technique to conduct spatial analyses on OD travel patterns of regional mobility services based on reconstructed OD data derived from re-aggregation for original OD distributions. Based on the reconstructed OD data that contains information on the inherent feature vectors of the original OD data, the proposed method enables analysis of the spatial characteristics of regional mobility services, including public transit bus, taxi and DRT.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.1
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• pp.52-64
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• 2023

This paper concentrated on estimating the travel time value of individual regional bus passengers in various in-vehicle crowding conditions. In the analysis model, the traffic-selection data of individual transportation passengers based on smart-card data were used. Variables which reflect the level of in-vehicle crowding and the variables of in-vehicle travel time that reflect the level of in-vehicle crowding were included in the model using Box-Cox transformation. The result of this paper indicates that the travel time value experienced by individual users would increase as the in-vehicle crowding level increases. The smart card data used in this paper is considered to have significant implications in terms of conducting more sophisticated and realistic qualitative research to reflect the values of variables for in-vehicle traffic hours and in-vehicle crowding levels, which previously had limitations in observation and quantification. It is expected that the effects of improvement measures for reducing congestion on regional buses can be considered quantitatively by applying the estimation results of crowding multiplier.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.2
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• pp.136-142
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• 2023

In the past, the efficiency of solar cells had been increased in order to increase the efficiency of solar modules. However, in recent years, in order to increase output in the solar industry and market, the competitiveness of solar cells based on large-area solar cells and multi-bus bar has been increasing. Multi-busbar solar module is a technology to reduce power loss by increasing the number and width of the front busbar of the solar cell and reducing the current value delivered by the busbar by half through half-cutting. In the case of the existing M2 (156.75×156.75 mm²) solar cell, even with a half-cut, power loss could be sufficiently reduced, but as the area of the solar cell is enlarged to more than M6 (166×166 mm²), the need for more divisions emerged. This affected not only solar cells but also inverters required for module array configuration. Therefore, in this study, the electrical characteristics of a large-area solar cell and after division were extracted using Griddler simulation. The output characteristics of the module were predicted by applying the solar cell parameters after division to PSPice, and a guideline for the large-area solar module design was presented according to the number of divisions of the large-area solar cell.

• Journal of Information Science Theory and Practice
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• v.10 no.spc
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• pp.56-65
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• 2022

Korea Institute of Science and Technology Information (KISTI) is a Worldwide LHC Computing Grid (WLCG) Tier-1 center mandated to preserve raw data produced from A Large Ion Collider Experiment (ALICE) experiment using the world's largest particle accelerator, the Large Hadron Collider (LHC) at European Organization for Nuclear Research (CERN). Physical medium used widely for long-term data preservation is tape, thanks to its reliability and least price per capacity compared to other media such as optical disk, hard disk, and solid-state disk. However, decreasing numbers of manufacturers for both tape drives and cartridges, and patent disputes among them escalated risk of market. As alternative to tape-based data preservation strategy, we proposed disk-only erasure-coded archival storage system, Custodial Disk Storage (CDS), powered by Exascale Open Storage (EOS), an open-source storage management software developed by CERN. CDS system consists of 18 high density Just-Bunch-Of-Disks (JBOD) enclosures attached to 9 servers through 12 Gbps Serial Attached SCSI (SAS) Host Bus Adapter (HBA) interfaces via multiple paths for redundancy and multiplexing. For data protection, we introduced Reed-Solomon (RS) (16, 4) Erasure Coding (EC) layout, where the number of data and parity blocks are 12 and 4 respectively, which gives the annual data loss probability equivalent to 5×10^-14. In this paper, we discuss CDS system design based on JBOD products, performance limitations, and data protection strategy accommodating EOS EC implementation. We present CDS operations for ALICE experiment and long-term power consumption measurement.

• Journal of the Korean Institute of Rural Architecture
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• v.24 no.4
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• pp.1-8
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• 2022

This study aims to investigate the gap in accessibility to urban planning facilities between living spheres in local small and medium-sized cities. In this study, OD data between administrative dongs of public transportation users was constructed to analyze the living shpere, and community analysis was conducted based on cohesion between data. As a result of the analysis, it was confirmed that a total of 10 clusters (mid-living areas) were formed, and the topographical difference between the 11 middle living areas established in the existing Jinju City Basic Plan and the single living areas were actively exchanged to form a community with other administrative dongs. Next, the analysis of the service area of urban planning facilities for mid-living areas was conducted based on the road network. As a result of analyzing the area accessible within 5, 10, and 15 minutes, educational facilities, public facilities, cultural facilities, tourism, and green facilities could be reached within 15 minutes in most mid-living areas. On the other hand, there were many areas where access to transportation facilities, medical facilities, and cultural facilities was difficult within 15 minutes. In particular, the accessibility of the outer living area and the central living area were different. To improve the quality of life of citizens, using urban planning facilities in Jinju-si and establishing related plans in urban basic plans, it is necessary to conduct a study on service areas through network analysis.

• Smart Structures and Systems
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• v.29 no.5
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• pp.661-675
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• 2022

In this paper, an electric vehicle drives with efficient control and low cost hardware using four quadrant DC converter with Permanent Magnet Direct Current (PMDC) motor fed by DC boost converter is presented. The main idea of this work is to improve the energy efficiency of the conversion chain of an electric vehicle by inserting a boost converter between the battery and the four quadrant-DC motor chopper assembly. Consequently, this method makes it possible to maintain the amplification gain of the 4 quadrant chopper constant regardless of the battery voltage drop and even in the presence of a fault in the battery. One of the most important control problems is control under heavy uncertainty conditions. The higher order sliding mode control technique is introduced for the adjustment of DC bus voltage and mechanical motor speed. To implement the proposed approach in the automotive field, experimental tests were carried out. The performances obtained show the usefulness of this system for a better energy management of an electric vehicle and an ideal control under different operating conditions and constraints, mostly at nominal operation, in the presence of a load torque, when reversing the direction of rotation of the motor speed and even in case of battery chamber failure. The whole system has been tested experimentally and its performance has been analyzed.

• Design Convergence Study
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• v.15 no.5
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• pp.199-211
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• 2016

The study examined how age-friendly their living environments the aged perceived and it's significant difference depending on their characteristics. The subject were 96 old persons who aged more than 60 years and lived in Nagasaki city, Japan. They asked how far each neighborhood facility related to the aged was located from their houses, and the age-friendliness of walk way, traffic, multi-family houses for the aged, and interior space of their living houses. Data were collected by using one to one interview. Results were as follows: 1) Most neighborhood facilities related to the aged were located within a walking distance or 10 min. distance by bus from their houses. 2) Among 5 areas of living environments, while traffic, house interior, and pedestrians road were relatively age-friendly, the amount of multi-unit dwellings for the elderly and the usability of wheelchair users in house interior were not age-friendly. 3) Age and education level of the aged influenced on the age-friendliness of their living environments.