• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.5
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• pp.100-111
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• 2019

The existing selected station analysis (SSA) method analyzes the link transfer mode data between origin and destination of individuals passing through stations from a microscopic standpoint. As such, existing SSA is insufficient as it uses integrated analysis using macroscopic data such as subway lines. This research builds a line chain OD based on path search of individual passenger's movement through the subway, and explores means to utilize the findings. First, a method is proposed that searches the traversed subway path from the linked passage modes that the passenger uses and applies the results to SSA line analysis. Compared to the existing SSA, this method provides for analysis of commonly conflicting features such as the line on which the station is passed, and the stations included on the line thanks to the presence of complete information of the individual passenger's traversed path. It also allows for integrated observation of the line chain OD that approaches a certain station. For enhanced understanding, Seoul Metro Line 9 is used as a case study to demonstrate the integrated formulation concept of line chain OD centered around a certain station as well as the macroscopic features of the traversed path that approaches stations included on the line.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.443-452
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• 2011

This study analyzed passenger travel patterns especially for the transfer from metro to bus by using transit smart card data. We classified three types of land use such as residential, business, and shopping area where metro stations are located. The results show that more number of transfers was observed at residential area compared to that of shopping and business area. Also, more number of transfers from metro to arterial bus was observed than that of transfers to local bus. Further, the high number of transfers to arterial bus was observed at business and shopping area. This means that the transfer to bus at metro stations varies by land use. The egress walk distance from metro station was found to be approximately 400 meters and the average walk distance of young people was found to be shorter than that of the old.

• Convergence Security Journal
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• v.20 no.4
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• pp.217-225
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• 2020

In recent years, the "social distance" has drastically reduced overseas travelers. On the other hand, for personal safety and security, it is expected that interest and demand for CCTV, electric alarm and signaling devices, electric diagnostics and medical devices will increase significantly. The purpose of this paper is to find out the effect of airport transfer passengers and exports of CCTV, electrical diagnostics and medical devices, electrical alarms and signaling devices on exports to Korea, and the synchronism of each variable. To this end, this study used a total of 231 monthly data from January 2000 to April 2020 in the National Statistics Service. As a result of empirical analysis, CCTV and electrical diagnostics and medical devices showed relatively high synchronization with respect to exports to Korea. Electric alarms & signaling devices and transit passengers also showed a certain level of synchronization with exports, but were relatively weak.

• Journal of Korean Society of Transportation
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• v.26 no.5
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• pp.227-235
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• 2008

This study analyzed the efficiency of a trunk with branches and a trunk with feeders route system comparing the user cost and operator cost of those route systems. Basically, a trunk with branches is more efficient than a trunk with feeders in the passengers' perspective if the transit system of a trunk and feeders are the same. In the case that the trunk system is hierarchically higher than the feeder system, a trunk with feeders has the competitive edge over a trunk with branches if the saving of travel cost induced by using the trunk line is larger than the increasing waiting and transfer cost. This result is consistent with the previous research by Park et al.(2007c), which analyzed the efficiency of hierarchical structure in a grid transit network. If the travel demand of each origins and destinations is low, increasing headway according to the travel demand can increase passenger load or operating efficiency in a trunk with feeders route system. In this case, a trunk with feeders route system is more prevalent as the operating cost, route length, and number of destinations increases, while it is less prevalent as the transfer cost and passengers' time value of the waiting time increases. In cases that central business district, which is located in the middle of a trunk line, generates travel demand, a trunk with feeders is more efficient than a trunk with branches with the increasing travel demand from and to the CBD. Therefore it can be concluded that to have a dual operating system between CBD and suburban is more efficient than one type transit system. The efficiency of that system can be increased through an efficient transfer system that can reduce the transfer cost.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2913-2917
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• 2007

Turbocharger has been widely used in many passenger cars in application with diesel engines because of high power and fuel efficiency. However, flow-induced noise (whoosh or hissing noise) which is generated within the compressor during its operation at marginal surge line can deteriorate noise characteristics. Hissing noise excitation was associated with the generation of turbulence within the turbocharger compressor and radiated through the transmission path in turbocharger system. In this study, a sharp-edged reactive-type muffler was devised and installed in the transmission path to reduce the hissing noise. Acoustic and fluid dynamic characteristics for the muffler were investigated which is related to the unsteadiness of turbulence and pressure in turbocharger system. A transfer matrix method was used to analyze the transmission loss of the muffler. Simple expansion muffler with extended tube of the reactive type is proposed for the reduction of high frequency component noise. Turbulence computation was carried out by a standard ${\kappa}-{\varepsilon}$ model. An optimal design condition of the muffler was obtained by extensive acoustic and fluid dynamic analysis on the engine dynamometer with anechoic chamber. A significant reduction of the hissing noise was achieved at the optimal design of the muffler as compared with the conventional turbocharger system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.1
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• pp.153-160
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• 2001

A general procedure for the design sensitivity analysis of structural dynamic problems has been presented in frame of the FRF-based substructuring formulation. For a system response function, the proposed method gives a parametric design sensitivity formula in terms of the partial derivatives of the connection element properties and the transfer matrix of the subsystems. The derived design sensitivity formula is applied to an engine mount system. An interior noise problem in the passenger car is analyzed using the FRF-based substructuring method and the proposed formulation is adopted to study the response variations with respect to the dynamic characteristics of the engine mounts and the bushes. To obtain the FRFs, a finite element model is built for the engine mount structures, and test data is used for the trimmed body including cabin cavity. The comparison of sensitivities derived by the proposed method and the finite difference method shows that the proposed method is efficient and accurate. The proposed sensitivity analysis method indicates effectively the most sensitive location to the interior noise among the engine mounts and the bushes.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.4
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• pp.177-181
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• 2017

Auxiliary power supply for railway vehicle is a equipment that focuses on the service of passengers in a vehicle. It supplies power to controllers used in heating and cooling devices, fluorescent lamps, batteries and many other electrical equipments. Most of the auxiliary power supply for railway vehicle are mainly used for the round trips and circulation routes within the metropolitan area and have a capacity of 170~200 kVA. In this study, we developed the auxiliary power supply capacity to 240kVA for 200km/h class. As such, the auxiliary power supply is an important device for securing the reliability and safety of the railway vehicle and improving the passenger convenience, so the performance verification of the performance must be ensured. In this paper, 240kVA auxiliary power supply is developed. Also, performance of the auxiliary power supply manufactured through the analysis of various characteristics related to the auxiliary power supply was confirmed while operating the actual line.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.7 s.100
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• pp.799-805
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• 2005

This paper describes the development process of high stiffness body for ride and handling performance. High stiffness and light weight vehicle is a major target in the refinement of Passenger cars to meet customers' contradictable requirements between ride and handling performance and fuel economy This paper describes the analysis approach process for high stiffness body through the data level of body stiffness. According to the frequency band. we can suggest the design guideline about lg cornering static stiffness, torsional and lateral stiffness, body attachment stiffness. The ride and handling characteristic of a vehicle Is significantly affected by vibration transferred to the body through the chassis mounting points from front and rear suspension. It is known that body attachment stiffness is an important factor of ride and handling performance improvement. And high stiffness helps to improve the flexibility of bushing rate tuning between handling and road noise. It makes possible to design the good handling performance vehicle and save vehicles to be used in tests by using mother car at initial design stage. These improvements can lead to shortening the time needed to develop better vehicles.

• Journal of Korea Multimedia Society
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• v.23 no.2
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• pp.255-261
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• 2020

As the accidents of cargo and passenger carrying ships occur, the stress faced by the vessel users is increasing. The risk factors for accident deterioration in remote marine area are stronger than those in road accidents, and therefore the need for safety control is greatly emphasized. To overcome such issue, a lot of effort has been made in terms of conducting research and development of the passengers and freights location tracking system. However, the inner bulkhead structures are made of aluminum/steel which is a difficult material to transfer location information through. This study aims to measure the receiving rate of LoRaWAN signal inside the aluminum/steel bulkhead structures with variation in reception strength and distance. The test was taken place at platforms with 6T and 8T enclosures to reflect the same conditions found in fishery patrol boats. The receiving rate of through-the-wall communication at 10M distance turned out to be 86% in case of using two 6T enclosures, and 73% in case of using one 8T enclosure. The result showed that the receiving rate was more affected by the thickness rather than the number of enclosures.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.678-680
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• 1998

Based on fuzzy logic algorithm this paper constructed fuzzy logic controller for automated vehicles. For passenger's convenience especially comfortability controller need to reduce the frequency of input variable's changing. So we established membership functions for comfortability as mil as speed following. It made possible to control comfortability directly. To demonstration the efficiency of fuzzy logic controller, we carried out simulation with a Automobile's transfer function. First, we designed the PID controller by using Ziegler-Nichols tunning method. Second, we calculated time response for each controller, then we compared the speed patterns of fuzzy controlled system and PID controlled system. Also we compared the difference of input variable. By comparing two controller's response, we can confirm the merit of fuzzy controller about comfortability. Fuzzy controller can reduce input changing frequency.