• Proceedings of the KSR Conference
• /
• 2003.10b
• /
• pp.319-325
• /
• 2003

This study focuses on the efforts of rail freight industry in Europe to adapt to the change of freight market. Nearly $80\%$ of freight is transported in short and medium distance market and due to e-commerce the freight becomes small and requires more frequencies than before. Rail freight industry tries to change their operation practices and to create measures to catch the market share. Trials in the two market segments, sea port to/from inland rail terminal and airport to/from inland rail terminal, are reviewed in this study.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1992.10a
• /
• pp.61-64
• /
• 1992

Recently, by the lack of fill material, the dredg and fill(hydraulic fill) method is commonly used in reclamation projects. Hydraulic fill method dredges the soil and send it with water through the transportation pipe to the site. The intial state of the hydraulic fill material is accordingly the mixture of water and soil skeleton which settles with time forming a new soil layer. The properties of new soil layer is governed the size of the soil skeleton, the flow velocity of mixing water, salt concentration, the distance from the discharge pipe outlet, and other dredging conditions when settling process occur. In this study, the effects of gradation of derdged soil on the deposition properties (with emphasis on the optimum spacing of the discharge pipes) was investigated by field test. It was found that the soft fine graind soil was forme at 350m from the discharge pipe outlet when the dredged material was classified as CL, while the soft fine grained soil was not formed even at the distance farther than 400m from the diacharge pipe outlet when the dredged material was classified as SM.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2014.10a
• /
• pp.87-88
• /
• 2014

The Coastal sediment is highly contaminated due to ship transportation, industries discharges and urban sources. Various contaminants release into seawater and settle in marine sediment and it significantly affect marine eco system. In the present study evaluated the optimization of slow release biostimulant ball (BSB) in coastal sediment in busan. The effective variables like BSB size, distance and month variables on VS reduction was determined by using Response surface methodology(RSM). The analysis of variance (ANOVA) and coefficient determination (R2) of VS was 0.9369 and maximum reduction of VS was obtained in 3cm ball size and 5.5cm distance and 4 month interval time. This result revealed that the BSB in effective VS reduction in coastal sediment.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.5
• /
• pp.883-887
• /
• 2016

The power supply system in Korean electrified railway has adopted AT feeding. If a fault occurs in some substation for any reason, the vicinity substation must feed electric power on the outage substation through catenary. So, the feeding distance grows twice of the normal state at extended feeding condition. If substation's feeding distance is longer than normal condition, the catenary impedance and train to supply electric power from the substation. Therefore, the severe voltage drop can occur and power supply shall be not allowed. This paper presents the model of compensator against voltage drop using multi-port network algorithm. Whole traction power supply system can be analyzed with this model. Computer simulation including this model is performed based on real train schedule and increased schedule in case studies.

• Proceedings of the KIEE Conference
• /
• 2001.07d
• /
• pp.2393-2395
• /
• 2001

The mobile robot is used as an instrument of transportation in automated plant. But the greater part of the moving method is the wheel-type. The wheel-type robot is easier control than the track-type, However the track-type is better than the wheel-type in bad landform(bend landform, an incline plane, stairs). In this paper, we propose the navigation algorithm of track-type robot in order to improve a defect of wheel-type. We experiment in bend landfrom and even ground to differentiate the navigation method. To estimate robot pose, we use the 80196 in a close distance and the vision-board in a long distance. Each data is managed in main PC and then the part of managing correspond to every sensor. We also use twelve supersonic wave-sensors to recognize external surroundings. As the result of experiment, we analyze the algorithm of control and make possible surroundings-adaptation.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.846-853
• /
• 2008

Maglev System is expected to be a new public transportation for future because of its special characteristics. Sleepers of railway role on transferring the lateral load to guideway for Maglev and controlling the distance between rails. Variation of distance of sleepers can affect dynamic responses for maglev guideway. In this paper, Daejon maglev guideway is analyzed to find proper tie spacing of a maglev system. The analysis included using a maglev trainload and also the dead load as the primary forces on bridges. Not only the dynamic behavior of bridges is investigated under sleeper conditions, but also impact factor about vertical displacement on the guideway is produced. This guideway is analyzed in four cases followed by changing spacing of sleeper and then obtained dynamic characteristics such as displacements, acceleration and impact factor by Finite Element Analysis.

• International Journal of Computer Science & Network Security
• /
• v.21 no.12
• /
• pp.257-263
• /
• 2021

Though many have studied choosing one of the alternative ways to reach a destination, the factors such as average road speed, distance, and number of traffic signals, traffic congestion, safety, and services still presents an indisputable challenge. This paper proposes two approaches: Appropriate membership function and ambiguous rule-based approach. It aims to tackle the route choice problem faced by almost all drivers in any city. It indirectly helps in tackling the problem of traffic congestion. The proposed approach considers the preference of each driver which is determined in a flexible way like a human and stored in the driver profile. These preferences relate to the criteria for evaluating each candidate route, considering the average speed, distance, safety, and services available. An illustrative case study demonstrates the added value of the proposed approach compared to some other approaches.

• ETRI Journal
• /
• v.45 no.5
• /
• pp.758-767
• /
• 2023

In this study, we introduce a loosely coupled relative position estimation method that utilizes a decentralized ultrawideband (UWB), Global Navigation Support System and inertial navigation system for flight controllers (FCs). Key obstacles to multidrone collaboration include relative position errors and the absence of communication devices. To address this, we provide an extended Kalman filter-based algorithm and module that correct distance errors by fusing UWB data acquired through random communications. Via simulations, we confirm the feasibility of the algorithm and verify its distance error correction performance according to the amount of communications. Real-world tests confirm the algorithm's effectiveness on FCs and the potential for multidrone collaboration in real environments. This method can be used to correct relative multidrone positions during collaborative transportation and simultaneous localization and mapping applications.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.14 no.1
• /
• pp.81-88
• /
• 2005

There have been many studies on generation equipment and plant piping, but there is no significant study result on the heat transportation pipe. As such, this study established basic theory on the compensated method among buried pipe for regional heating, and further obtained the following results by applying the conditions of AGFW and NCHPP respectively in calculation of friction and maximum installation distance for the buried pipe. Friction coefficient according to the types and physical properties of soil, friction and maximum installation distance were compared to set the application value of friction coefficient according to the location of works. Calculation formula of clay load to be applied for calculation of friction was introduced to the formula of AGFW and the formula of NCHPP that has been used in Nowon district since 1997 to determine the difference and applicability. $120^{\circ}C$ and $95^{\circ}C$ were applied in temperature difference for expansion volume to compare the arm length at the curve pipe so thai it can be reflected in the design in the future. Maximum installation distance according to thickness of pipe was compared to present the necessity of unified specification so that same kinds of pipe materials can be used for same kinds of works.

• Geomechanics and Engineering
• /
• v.6 no.3
• /
• pp.263-275
• /
• 2014

The development of transportation in large cities requires the construction of twin tunnels located at shallow depth. As far as twin tunnels excavated in parallel are concerned, most of the cases reported in literature focused on considering the effect of the ground condition, tunnel size, depth, surface loads, the relative position between two tunnels, and construction process on the structural lining forces. However, the effect of the segment joints was not taken into account. Numerical investigation performed in this study using the $FLAC^{3D}$ finite difference element program made it possible to include considerable influences of the segment joints and tunnel distance on the structural lining forces induced in twin tunnels. The structural lining forces induced in the first tunnel through various phases are considerably affected by the second tunnel construction process. Their values induced in a segmental lining are always lower than those obtained in a continuous lining. However, the influence of joint distribution in the second tunnel on the structural forces induced in the first tunnel is insignificant. The critical influence distance between two tunnels is about two tunnel diameters.