• Journal of Korean Tunnelling and Underground Space Association
• /
• v.17 no.3
• /
• pp.257-266
• /
• 2015

This study introduce that we studied optimization and possibility of smoke spread prevention with air-curtain system in undersea tunnel named from Ho-Nam to Jeju line in domestic if a fire break out in train. To verify performance, air-curtain system is installed between rescue station platform and each door of passenger car to provide safety route to evacuator and we studied simulation model of various cases about 15 MW fire severity considering domestic specifications. As a result we verified the fact that CASE1(air jet with 15degree toward passenger car) and CASE 5 (air jet with 15degree toward passenger car and pressure air blast from cross passage) is best Smoke Spread Prevention and less inflow carbon monoxide. Through above results, we expect that air-curtain system is one of the facilities for fire safety and provide us safety platform route in undersea tunnel.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.40 no.5
• /
• pp.397-409
• /
• 2003

This paper describes an implementation of radix-4 trellis parallel architecture and backward state transition control trace back Viterbi decoder, and presents the application results to high speed wireless LAN. The radix-4 parallelized architecture Vietrbi decoder can not only improve the throughput with simple structure, but also have small processing delay time and overhead circuit compared to M-step trellis architecture one. Based on these features, this paper addresses a novel Viterbi decoder which is composed of branch metric computation, architecture of ACS and trace back decoding by sequential control of backward state transition for the implementation of radix-4 trellis parallelized structure. With the proposed architecture, the decoding of variable code rate due to puncturing the base code can easily be implemented by the unified Viterbi decoder. Moreover, any additional circuit and/or peripheral control logic are not required in the proposed decoder architecture. The trace back decoding scheme with backward state transition control can carry out the sequential decoding according to ACS cycle clock without additional circuit for survivor memory control. In order to evaluate the usefulness, the proposed method is applied to channel CODEC of the IEEE 802.11a high speed wireless LAN, and HDL coding simulation results are presented.

• Korea Real Estate Review
• /
• v.28 no.1
• /
• pp.7-21
• /
• 2018

This study was conducted to determine the location determinants that influence the sales of the "Storyway" convenience stores built at the country's railway stations. The preceding studies were about the convenience stores located in the residence-business areas or along the roadsides. This study, on the other hand, focused on the characteristics of the stations, based on a theory that is different from the existing theories. The targets of this study were the 301 "Storyway" convenience stores doing business in the 198 railway stations in the country, and the dummy parameter and hedonic-price model function were used for multiple regression analysis. For the study results, it was found that the number of people using the railway and the size of the store have a positive effect on the sales whereas the other brand competitors have a negative effect thereon. Second, the subway stations holding 89% of the total passengers in the country have unexpectedly no positive influence on the sales. Third, depending on the transfer, it was found that no transfer station had smaller sales than the transfer stations. Finally, as for the location of the stores in the station, the stores located on the platforms or passageways have a smaller turnover rate than the stores in the welcoming spaces and squares. This research result shows that when starting a convenience store business, the number of people using the railway, the size of the store, the transfer possibility, and the location of the store inside the station have to be considered under the circumstance of recession on the part of the convenience stores due to excessive competition.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.06a
• /
• pp.721-723
• /
• 2007

Recently, the size and location of the acquired container image while the container is loading and unloading in Harbors is not fixed. And it is difficult to get a good image for recognition because of the variation of external environment as those the size of container and where the yard-tractor stop is. In this paper, we estimate where the container ISO-code set is using Top-hat transform from realtime images and get an image to recognize container ISO-code using PAN/TILT/ZOOM camera. We extract the container ISO-code using Top-hat transform and Histogram projection. After binarization, we extract each character from complex background using labeling. We use BP(Backpropagation Network) to recognize extracted characters.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.40 no.11
• /
• pp.51-62
• /
• 2003

This paper presents a novel survivor memeory management and decoding techniques with sequential backward state transition control in the trace back Viterbi decoder. The Viterbi algorithm is an maximum likelihood decoding scheme to estimate the likelihood of encoder state for channel error detection and correction. This scheme is applied to a broad range of digital communication such as intersymbol interference removing and channel equalization. In order to achieve the area-efficiency VLSI chip design with high throughput in the Viterbi decoder in which recursive operation is implied, more research is required to obtain a simple systematic parallel ACS architecture and surviver memory management. As a method of solution to the problem, this paper addresses a progressive decoding algorithm with sequential backward state transition control in the trace back Viterbi decoder. Compared to the conventional trace back decoding techniques, the required total memory can be greatly reduced in the proposed method. Furthermore, the proposed method can be implemented with a simple pipelined structure with systolic array type architecture. The implementation of the peripheral logic circuit for the control of memory access is not required, and memory access bandwidth can be reduced Therefore, the proposed method has characteristics of high area-efficiency and low power consumption with high throughput. Finally, the examples of decoding results for the received data with channel noise and application result are provided to evaluate the efficiency of the proposed method.

• The Journal of the Acoustical Society of Korea
• /
• v.34 no.5
• /
• pp.385-393
• /
• 2015

The speed of train has rapidly been increased in accordance with the developed railway technology. Nowadays, high-speed trains were introduced which has the speed faster than 400 km/h. In Korea, a lots of efforts were undertaken to increase the speed of train faster than 350 km/h, however noise and vibration are still the main problems to solve for realization of the high-speed train. In the case of operation speed faster than 350 km/h, it can be easily presumed that the noise and vibration damages could be increased in the train stations which are close to the passing railway tracks. Thus, the noise in the five different types of high-speed train stations were analyzed including stations built on the ground, underground, under rail, and two types on rail. The present paper predicts noises inside the stations depending on the speed of the passing trains and analyze the noise comparing with noise criteria (NC). Sound insulation performance of each part of buildings was calculated using the transmission noise formula and computer modeling, Finally, a series of processes were introduced to satisfy the aural environment with the optimum interior noise criteria by changing interior finishing materials.

• Journal of the Korean Society for Railway
• /
• v.12 no.4
• /
• pp.526-534
• /
• 2009

PRT(Personal Rapid Transit) can be described as a system of driverless taxicabs, that. automatically take passengers to their destinations along dedicated guideways, without intermediate stops.It is ideally suited as a short feeder transportation for on-demand circulation operations at train stations, airports, office complex, amusement park and shopping center. This PRT study do suggest that a PRT system could provide a high level of mobility to the commuters making work trips, workers making work, shopping and other non-work trips, residents making shopping and other non-work trips and recreational riders.This study presents the possibilities of PRT applications in national level. As the technology continues to advance, there may be opportunities to improve the reliability, and efficiency of our future public transportation systems.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.24 no.3
• /
• pp.247-262
• /
• 2022

In domestic tunnels, it is mandatory to install CCTVs in tunnels longer than 200 m which are also recommended by installation of a CCTV-based automatic accident detection system. In general, the CCTVs in the tunnel are installed at a low height as well as near by the moving vehicles due to the spatial limitation of tunnel structure, so a severe perspective effect takes place in the distance of installed CCTV and moving vehicles. Because of this effect, conventional CCTV-based accident detection systems in tunnel are known in general to be very hard to achieve the performance in detection of unexpected accidents such as stop or reversely moving vehicles, person on the road and fires, especially far from 100 m. Therefore, in this study, the region of interest is set up and a new concept of inverse perspective transformation technique is introduced. Since moving vehicles in the transformed image is enlarged proportionally to the distance from CCTV, it is possible to achieve consistency in object detection and identification of actual speed of moving vehicles in distance. To show this aspect, two datasets in the same conditions are composed with the original and the transformed images of CCTV in tunnel, respectively. A comparison of variation of appearance speed and size of moving vehicles in distance are made. Then, the performances of the object detection in distance are compared with respect to the both trained deep-learning models. As a result, the model case with the transformed images are able to achieve consistent performance in object and accident detections in distance even by 200 m.

• Journal of the Korean Society for Railway
• /
• v.20 no.1
• /
• pp.1-10
• /
• 2017

Brake squeal noise has been a challenging problems for a long time. It is very annoying to passengers and residents near tracks. Two methods have been applied to reduce or eliminate brake squeal noise. One is to improve frictional materials; the other is to optimize the topology and structures of brake pads. In this study, we developed two kinds of brake pads; one is a pad whose frictional material is different from the KTX brake pad friction material; the other is a flexible pad that has the same frictional material as that of the KTX brake pad, but a different structure. Squeal noise and friction coefficients were measured and analyzed using a full-scale brake dynamometer. It was found that the dynamometer test can simulate the squeal noise of KTX trains at stations. The squeal frequency of the KTX at 4500Hz was exactly reproduced; this value of 4500Hz was one of the natural frequencies of the KTX brake disc. It was also found that the squeal noise depended on the caliper pressure, initial disc temperature and braking speed. The average friction coefficient was 0.35~0.45. The new pad lowered the squeal noise by 17.3~21.6dB(A).

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.4
• /
• pp.443-449
• /
• 2012

This study was conducted to investigate the antioxidant and acetylcholinesterase (AChE) inhibitory activities of extracts from various seaweed. The extracts of $Sargassum$ $thunbergii$ (91.3%), $Polysiphonia$ $morrowii$ (90.7%), $Ecklonia$ $cava$ (89.9%), and $Artemisia$ $fukudo$ (85.9%) showed over 80% high radical scavenging activities at the final concentration of 40 ${\mu}g$/mL. The $Artemisia$ $fukudo$ extract showed the highest inhibition activity of 30.2% on AChE at the final concentration of 10 ${\mu}g$/mL. The extract of $Porphyra$ $tenera$, $Costaria$ $costata$, $Monostroma$ $nitidum$, $Ecklonia$ $cava$, and $Agarum$ $clathratum$ against AChE at a concentration of 10 ${\mu}g$/mL exhibited inhibition of 26.6%, 25.3%, 23.4%, 21.7%, 20.4% and 19.9%, respectively. The bioautography results showed that the mixtures of structurally diverse compounds were thought to affect AChE inhibitory activity. These results suggest that extracts from seaweed with their high quality components may be effective in the prevention of Alzheimer's disease and may be used to develop various functional food products.