• Journal of the Korean Society for Railway
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• v.13 no.3
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• pp.309-316
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• 2010

When the horizontal and vertical curves are superimposed in railway alignments, which affects the running stability, ride comfort, and track maintenance costs. However, when designing new lines or realigning existing ones, there are many cases of superimposition caused by the existing fixed points (bridge, tunnel, turnout, and catenary system, etc) on the conventional lines and undesirable impacts on the environment, etc. In this study, when the horizontal and vertical curves are superimposed, in order to optimize the horizontal curve in aspect of the ride comfort, the object function was developed and verified by vehicle dynamic analysis. Also, the solution algorithm for simplified evaluation method was presented.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1818-1823
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• 2015

In this paper, we analyzed the optimal configuration of protection wire that have been installed in the electric railway power supply system. Protection wires are to suppress the ground potential rise when the short circuit fault between contact wire-rail(C-F), and protect the electronics equipments(signalling and communication) that are facility the wayside. The role of protection wires must be feed back quickly the fault current to the substation when a short circuit fault occurs. In this paper, we proposed that only one line to install the protection wire. Comparing how to newly proposed and existing system, most of the performance is similar. The reason is that most of the current flowing in the protection wire near the location where the fault occurred. There is no problem even if in one line for human safe and the low impedance of the return circuit in dimension to ensure the safety of the facility during the fault. To ensure safety during an fault occurs, it is sufficient even by one line. But, In the protection wire of facilities planning it is necessary to design taking into account the potential utility.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.12 no.1
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• pp.37-43
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• 2006

PURPOSE: Previous studies have documented the lack of ultrasound's non-thermal effects on nerve conduction using frequencies of 1 MHz and 870 kHz. The purpose of this study was to determine the biophysical effects of continuous ultrasound on median local forearm temperature and motor nerve conduction velocities using frequencies of 3.0 MHz. SUBJECTS: Twelve healthy subjects (6 males, 6 females, age $22.30{\pm}2.41$ yrs, weight $61.33{\pm}10.16$ kg, height $167.58{\pm}8.04$ cm) without a history of neurological or musculoskeletal injury to their dominant arm volunteered for this study. METHODS AND MATERIALS: Each subject received a total of five treatments, one each at .0, 0.5, 1.0, 1.5, 2.0 W/$cm^2$ of 3 MHz continuous ultrasound on the anterior surface of the middle area of dominant forearm for 10 minutes. Dependent measures for forearm local temperature and median motor nerve conduction velocity (MNCV) were taken pretreatment and immediately post-treatment. One-way ANOVA were used for each dependent measure. RESULTS: The posttreatment forearm local temperature were differed significantly (p<0.001) between intensities of ultrasound. The posttreatment forearm local temperature of the ultrasound treated with 1.0 w/$cm^2$, 1.5 w/$cm^2$ and 2.0 w/$cm^2$ were significantly higher than 0.5 w/$cm^2$ and 0.0 w/$cm^2$ of ultrasound (p<0.05). The posttreatment median MNCV were differed significantly from the respective pretreatment velocities (p<0.001). The MNCV of the ultrasound treated with 0.0 w/$cm^2$ and 0.5 w/$cm^2$ were significantly (p<0.05) slower than that observed pretreatment, while the three ultrasound intensities produced significantly increased posttreatment MNCV: 1.0 w/$cm^2$ and 1.5 w/$cm^2$ and 2.0 W/$cm^2$. The posttreatment MNCV at 2.0 w/$cm^2$ and 1.5 w/$cm^2$ was significantly faster than that at 0 w/$cm^2$, 0.5 w/$cm^2$ and 1.0 w/$cm^2$ (p<0.05), the MNCV at 1.0 w/$cm^2$ was significantly faster than that associated with 0 w/$cm^2$ and 0.5 w/$cm^2$ of ultrasound (p<0.05). CONCLUSIONS: The decreased median motor forearm local temperature and MNCV of the ultrasound treated with 0.0 w/$cm^2$ and 0.5 w/$cm^2$ were attributed to the cooling effect by ultrasound transmission gel. Local forearm temperature and nerve conduction velocity were directly related to the intensity of ultrasound. Alterations in MNCV from ultrasound on healthy nerves appeared to be related to temperature changes induced by thermal effects of ultrasound.

• Journal of the Korean Society for Railway
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• v.12 no.4
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• pp.582-589
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• 2009

The energy generated by braking vehicle would simply be converted into waste heat by its braking resistors if no other vehicle is accelerating at exactly the same time. Up to 45% of the tractive power of vehicles capable of returning energy to the power supply can be regenerated during braking and that this energy can be used to feed vehicles which are accelerating at the same time. Such synchronized braking and accelerating can not be coordinated, the ESS(energy storage system, here after) stores the energy generated during braking and discharges it again when a vehicle accelerates. The ESS is able to store and discharge energy extremely quickly, consequently enabling a complete exchange of energy between vehicles, even if they are not braking and accelerating at precisely the same time, as is most frequently the case in everyday service. The energy saving rate is related to the headway. If the headway is long/short, the energy saving goes up/down, When the headway is short, the ESS can not save much regenerative energy. The headway of SeoulMetro line 2 as the worst case is very short in Korea urban transit system. So, the energy saving rate will be very low. If the ESSs are applied to another railway system, we can expect that the effectiveness is better than the results of SeoulMetro line 2. This paper presents effects of energy saving obtained by applying the ESS to SeoulMetro line 2.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.3
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• pp.427-438
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• 2022

With the recent growing importance over safety management the need for advanced and technical approaches for on-site safety inspection methods has increased. Railway construction is subject to its own particular set of temporal and spatial challenges due to its unique facilities and equipment. This study aimed to investigate the field characteristics of railway infrastructure and improve the conventional field safety management methods by identifying the most appropriate features of AR technology. Group interviews and surveys were conducted with field safety experts to derive the major problems and inspection needs. Subsequently, various features of AR, such as BIM model projection, and remote conferencing, were investigated to determine their applicability to address safety issues. As a result, four problems in the current safety management process, such as 'lack of time due to the conventional inspection method and inspection of areas that are difficult to access', and three major inspection types, such as 'observance of work procedures, status of installation, adequate dimensional spacing', were identified to be improved when adopting AR based techniques. Furthermore, AR technology utilizing plans to solve safety inspection problems and effectively manage major inspection types were proposed, and a follow up survey was conducted with the same field safety experts to derive the priority of technology development.

• Journal of the Korean Society for Railway
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• v.13 no.1
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• pp.119-124
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• 2010

Light rail is an electric railway system, characterized by its ability to operate single or multiple car consists (trains) along exclusive rights-of-way at ground level, on aerial structures, in subways or in streets, able to board and discharge passengers at station platforms or at street, track, or car-floor level and normally powered by overhead electrical wires. Depending upon the specific system, the light rail lends some major advantages to urban settings. The evaluation of light rail technology as a potential component of regional transit systems has been the subject of extensive studies throughout the country in the past decade. For the study, feasibility was defined as "the ability of an LRT system to achieve certain level of transportation market in comparison with other transportation alternatives." This paper describes the feasibility study to evaluate a proposed light rail development project. The minimum are those LRT systems that would met to make a project feasible for further evaluation.

• Journal of IKEEE
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• v.24 no.1
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• pp.97-105
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• 2020

A thermal imaging sensor receives the radiating energy from the target and the background, so it has been widely used for detection, tracking, and classification of targets at night for military purpose. In recognizing the target automatically using thermal images, if the correct edges of object are used then it can generate the classification results with high accuracy. However since the thermal images have lower spatial resolution and more blurred edges than color images, the accuracy of the classification using thermal images can be decreased. In this paper, to overcome this problem, a new hierarchical classifier using both shape and local features based on the segmentation reliabilities, and the class/pose updating method for vehicle classification are proposed. The proposed classification method was validated using thermal video sequences of more than 20,000 images which include four types of military vehicles - main battle tank, armored personnel carrier, military truck, and estate car. The experiment results showed that the proposed method outperformed the state-of-the-arts methods in classification accuracy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6214-6220
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• 2015

A track circuit has used stably more than 100 years for detecting train position, but solution of track circuit sort circuit incapacity due to a rust is necessary for side line in station yard, coast line and level crossing for conventional line in rural line. Domestically, Axle Counter System(ACS) has partially used for Hot Box System for high speed line and turnout for CBTC system. In contrast, most of countries has used ACS not only trunk line but also rural line and its application has increased for metro, electric car and industrial railway. In this paper, we has verified the operating status of ACS which installed with existing track circuit through log analsis to implement pilot application in mail track and turnout in station yard. And interface test with interlocking system has conducted at Obong shunting yard, as well as Cheongju station and has analyzed test result. Based on a test result, we made fail safe design, manufacturing skill and established system requirement specification for the smooth operation and maintenance.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.5
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• pp.494-502
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• 2011

Bimodal tram is designed to run on a dedicated path in automatic mode using a magnetic track system in order to realize a combination of the accessibility of a bus and the constant regularity of a railroad. This paper presents design and test results of the series hybrid propulsion system of the bimodal tram on both test track and public road, which uses CNG (Compressed Natural Gas) engine and Lithium polymer battery pack. This paper describes the real-time data measuring equipment for the series hybrid propulsion system of the bimodal tram. Using this measurement equipment, the performance of the prototype vehicle's driving on test track and public road was verified and the fuel consumption and the efficiency of CNG engine have been investigated.