• Journal of Korea Planning Association
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• v.54 no.4
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• pp.71-78
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• 2019

Due to the rapid pace of low fertility and aging of Korea, population decline is rapidly progressing in the outskirts of the province and county. Demand for public transport is decreasing due to suburban population declines, while local government funding for maintenance of the bus system is expected to increase gradually. The government and municipalities are promoting the introduction of Demand Responsive Transport (DRT) in order to reduce the burden of financial support for buses while enhancing mobility of the residents in vulnerable areas. However, most DRTs in Korea have been operated mainly in the areas that are not provided with public transportation services. Although DRT is able to reduce the financial burden of local governments, it is not easy to be introduced because of the objection of the existing bus users. In this study, 11 out of 61 towns with poor public transportation services in Gyeongsangnam-Do were selected for the introduction of DRT to replace bus services by using village characteristics. The results of this study are expected to be used as a basis for decision making to use DRT instead of bus service for the burden of bus financing for local governments.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.3
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• pp.53-59
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• 2021

In vibration-free vehicles such as limousine buses, the vibration is minimized by installing an air spring instead of the leaf spring used in the existing freight cars to prevent the damage to the loaded cargo from shocks generated during movement. In the existing vehicles, steel structures support the air spring system. This study was aimed at replacing the steel structures used in the Z-spring by carbon fiber and glass fiber reinforced plastics. In addition, the mechanical properties (elastic modulus, tensile strength, and shear strength) of carbon fiber and glass fiber prepreg were derived using specimens molded with the corresponding prepreg. The final goal was to develop a material lighter than the conventional steel material but with enhanced mechanical properties. Although the CF prepreg exhibited excellent mechanical properties, the production cost was extremely high. To overcome this limitation, hybrid composites with GF prepreg were examined, which are expected to be promising future materials.

• International Journal of Computer Science & Network Security
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• v.22 no.3
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• pp.236-244
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• 2022

Network Mobility Basic Support (NEMO BS) protocol has been accredited and approved by Internet Engineering Task Force (IETF) working group for mobility of sub-networks. Trains, aircrafts and buses are three examples of typical applications for this protocol. The NEMO BS protocol was designed to offer Internet access for a group of passengers in a roaming vehicle in an adequate fashion. Furthermore, in NEMO BS protocol, specific gateways referred to Mobile Routers (MRs) are responsible for carrying out the mobility management operations. Unfortunately, the main limitations of this basic solution are pinball suboptimal routing, excessive signaling cost, scalability, packet delivery overhead and handoff latency. In order to tackle shortcomings of triangular routing and Quality of Service (QoS) deterioration, the proposed scheme (Diff-FH NEMO) has previously evolved for end-users in moving network. In this sense, the article focuses on an exhaustive analytic evaluation at Home Agent (HA) entity of the proposed solutions. An investigation has been conducted on the signaling costs to assess the performance of the proposed scheme (Diff-FH NEMO) in comparison with the standard NEMO BS protocol and MIPv6 based Route Optimization (MIRON) scheme. The obtained results demonstrate that, the proposed scheme (Diff-FH NEMO) significantly improves the signaling cost at the HA entity in terms of the subnet residence time, number of mobile nodes, the number of DMRs, the number of LFNs and the number of CNs.

• Journal of IKEEE
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• v.26 no.3
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• pp.437-444
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• 2022

This paper proposes a CRC error verification method for SPI and I2C buses of automotive semiconductors. In automotive semiconductors, when an error occurs in communication and an incorrect value is transmitted, fatal results may occur. Unlike LIN communication and CAN communication, in communication such as SPI and I2C, there is no frame for detecting an error, so some definitions of new standards are required. Therefore, in this paper, the CRC error detection mode is newly defined in the SPI and I2C communication protocols, and the verification is presented by designing it in hardware.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.1
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• pp.1-8
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• 2022

Recently, photovoltaic (PV) systems have been gradually applied in eco-friendly vehicle applications to improve fuel economy. The relevant market is expected to continue to grow because the installation of large-capacity PV systems to other eco-friendly vehicles, such as electric buses and trains, is being considered. However, in a PV system, power imbalance between submodules and low power generation efficiency occur due to factors such as cell aging, contamination, and shading. To resolve this problem, various differential power processing (DPP) converters have been researched and developed. However, conventional DPP converters suffer from large volume and low efficiency. Therefore, to apply DPP converters to eco-friendly vehicles, increasing efficiency and reducing volume and price compared with existing DPP converters is necessary. In this paper, a novel DPP converter with an integrated transformer is proposed and analyzed. The proposed DPP converter uses a single magnetic component by integrating transformers and secondary sides of conventional DPP converters. Therefore, the proposed DPP converter shows high power density and high efficiency, and it is suitable for PV systems in eco-friendly vehicle applications.

• IEMEK Journal of Embedded Systems and Applications
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• v.17 no.5
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• pp.273-280
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• 2022

Along with the advancement of deep learning technology, securing high-quality dataset for verification of developed technology is emerging as an important issue, and developing robust deep learning models to the domestic road environment is focused by many research groups. Especially, unlike expressways and automobile-only roads, in the complex city driving environment, various dynamic objects such as motorbikes, electric kickboards, large buses/truck, freight cars, pedestrians, and traffic lights are mixed in city road. In this paper, we built our dataset through multi camera-based processing (collection, refinement, and annotation) including the various objects in the city road and estimated quality and validity of our dataset by using YOLO-based model in object detection. Then, quantitative evaluation of our dataset is performed by comparing with the public dataset and qualitative evaluation of it is performed by comparing with experiment results using open platform. We generated our 2D dataset based on annotation rules of KITTI/COCO dataset, and compared the performance with the public dataset using the evaluation rules of KITTI/COCO dataset. As a result of comparison with public dataset, our dataset shows about 3 to 53% higher performance and thus the effectiveness of our dataset was validated.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.5
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• pp.88-97
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• 1995

The leaf spring is used in the suspension of most buses and trucks due to its compactness, which reduces the shock-force and the vibration from the road, and increases passenger comfortability and carlife. Of the various kinds of leaf springs, the leaf spring without eyes can be found easily in the heavy duty truck, and has different characteristics to the leaf spring with eyes in the case of large free camber. Because of radius change, the leaf without eyes slips on the supports, which makes the deflection. The difference is due to this deflection. In this paper, we show the general method of characteristic analysis, for example, Pandan method, can be no more applicable to these springs. Thus considering the geometry deflection by slip, we have developed the equation of the characteristic of the leaf spring without eyes and prove the effectiveness of this equation by experiment. From the result, at large camber the slip deflection is large and as camber smaller, this is smaller. At the camber behind some value, the effect of slip no longer influence to the characteristic of leaf springs.

• Annual Conference of KIPS
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• 2020.11a
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• pp.292-295
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• 2020

In the modern society, people can easily reach destination by using the rapidly developed public transportation services. Recently, location information is provided through the network, but this is useless to the weak people on transportation like the handicapped. This paper proposes a bus alert terminal system equipped with the arrival information of public buses based on location information and distance measurement sensor. By using this system, we look forward to providing more convenient and accessible services for the weak people on transportation.

• Health Policy and Management
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• v.33 no.3
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• pp.370-375
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• 2023

The responsibility to ensure the health rights of detainees, particularly their medical rights, fundamentally lies with the state in all nations. However, in the correctional facilities of the Republic of Korea, these rights are currently not adequately safeguarded. Numerous detainees express dissatisfaction with the medical services provided and show a preference for voluntary external treatment. However, barriers such as prolonged application processes for external treatment and the requirement for detainees to cover their medical expenses present significant challenges. Therefore, the National Human Rights Commission of Korea has advocated for an increased medical budget in correctional facilities and a bolstered professional medical workforce to improve the medical care of detainees. Recommendations for improvements include: (1) establishing dedicated correctional hospitals for detainees, (2) setting up specialized correctional wards, (3) collaborating with military hospitals, (4) launching mobile medical buses for diverse specialties, (5) enhancing collaboration with public and private medical institutions, (6) increasing compensation for partnering external medical institutions, (7) improving the working conditions of medical officers, (8) safeguarding the defense rights of medical staff, (9) improving the working conditions of public health doctors from the Ministry of Justice in correctional facilities, and (10) pre-assigning public health specialists and military doctors to correctional facilities. By implementing these measures, it is anticipated that the quality of medical services in the Republic of Korea's correctional facilities will improve, reducing the demand for external treatments among detainees and ensuring their health and medical rights are realistically upheld.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.4
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• pp.183-188
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• 2024

As time progresses and technology advances, many modes of transportation have emerged compared to the past. People use various means of transportation including personal cars, subways, buses, and taxis, among which public transport is utilized by people of all ages and genders. Public transportation has the advantage of being affordable and convenient, but with the increase in population compared to the past, traffic congestion has also been increasing, making it increasingly uncomfortable. Especially during specific times or on certain dates, traffic congestion can become significantly worse than usual. Among these, the subway is the mode of transportation used most frequently. Therefore, in this study, we will discuss solutions and analyze the causes of congestion by subway section using the R program.