• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.10a
• /
• pp.347-350
• /
• 2009

The opening of High-speed Rail provides convenience to move a long distance quickly, and the passengers of high-speed railway have been steadily increasing each year. Since the high-speed rail is far more expensive than other transportation, providing high quality service over just the high speed is required. Accordingly, much effort is made to improve service quality. However these services have been focused on general passengers so we should introduce a new service system to meet personal preferences of passengers. Therefore, in this paper, we introduce integrated railway service systems to provide service which follows the individual needs of passengers and is based on RFIDs (Radio Frequency Identification).

• Computers and Concrete
• /
• v.21 no.6
• /
• pp.717-726
• /
• 2018

Concrete pipelines are the most efficient and safe means for gas and oil transportation over a long distance. The use of nano materials and nono-engineering can be considered for enhancing concrete pipelines properties. the tests show that $SiO_2$ nanoparticles can improve the mechanical behavior of concrete. Moreover, severe hazard for pipelines is seismic ground motion. Over the years, scientists have attempted to understand pipe behavior against earthquake most frequently via numerical modeling and simulation. Therefore, in this paper, the dynamic response of underwater nanocomposite submerged pipeline conveying fluid is studied. The structure is subjected to the dynamic loads caused by earthquake and the governing equations of the system are derived using mathematical model via Classic shell theory and Hamilton's principle. Navier-Stokes equation is employed to calculate the force due to the fluid in the pipe. As well, the effect of external fluid is modeled with an external force. Mori-Tanaka approach is used to estimate the equivalent material properties of the nanocomposite. 1978 Tabas earthquake in Iran is considered for modelling seismic load. The dynamic displacement of the structure is extracted using differential quadrature method (DQM) and Newmark method. The effects of different parameters such as $SiO_2$ nanoparticles volume percent, boundary conditions, thickness to radius ratios, length to radius ratios, internal and external fluid pressure and earthquake intensity are discussed on the seismic response of the structure. From results obtained in this paper, it can be found that the dynamic response of the pipe is increased in the presence of internal and external fluid. Furthermore, the use of $SiO_2$ nanoparticles in concrete pipeline reduces the displacement of the structure during an earthquake.

• Computers and Concrete
• /
• v.24 no.2
• /
• pp.125-135
• /
• 2019

Concrete pipelines are the most efficient and safe means for gas and oil transportation over a long distance. The use of nano materials and nono-engineering can be considered for enhancing concrete pipelines properties. the tests show that SiO2 nanoparticles can improve the mechanical behavior of concrete. Moreover, severe hazard for pipelines is seismic ground motion. Over the years, scientists have attempted to understand pipe behavior against earthquake most frequently via numerical modeling and simulation. Therefore, in this paper, the dynamic response of underwater nanocomposite submerged pipeline conveying fluid is studied. The structure is subjected to the dynamic loads caused by earthquake and the governing equations of the system are derived using mathematical model via Classic shell theory and Hamilton's principle. Navier-Stokes equation is employed to calculate the force due to the fluid in the pipe. As well, the effect of external fluid is modeled with an external force. Mori-Tanaka approach is used to estimate the equivalent material properties of the nanocomposite. 1978 Tabas earthquake in Iran is considered for modelling seismic load. The dynamic displacement of the structure is extracted using differential quadrature method (DQM) and Newmark method. The effects of different parameters such as SiO2 nanoparticles volume percent, boundary conditions, thickness to radius ratios, length to radius ratios, internal and external fluid pressure and earthquake intensity are discussed on the seismic response of the structure. From results obtained in this paper, it can be found that the dynamic response of the pipe is increased in the presence of internal and external fluid. Furthermore, the use of SiO2 nanoparticles in concrete pipeline reduces the displacement of the structure during an earthquake.

• Applied Microscopy
• /
• v.52
• /
• pp.5.1-5.10
• /
• 2022

The use of Pipelines for long-distance transportation of crude oil, natural gas and similar applications is increasing and has pivotal importance in recent times. High specific strength plays a crucial role in improving transport efficiency through increased pressure and improved laying efficiency through reduced diameter and weight of line pipes. TRIP-based high-strength and high-ductility alloys comprise a mixture of ferrite, bainite, and retained austenite that provide excellent mechanical properties such as dimensional stability, fatigue strength, and impact toughness. This study performs microstructure analysis using both Nital etching and LePera etching methods. At the time of Nital etching, it is difficult to distinctly observe second phase. However, using LePera etching conditions it is possible to distinctly measure the M/A phase and ferrite matrix. The fraction measurement was done using OM and SEM images which give similar results for the average volume fraction of the phases. Although it is possible to distinguish the M/A phase from the SEM image of the sample subjected to LePera etching. However, using Nital etching is nearly impossible. Nital etching is good at specific phase analysis than LePera etching when using SEM images.

• Journal of Marine Life Science
• /
• v.2 no.1
• /
• pp.12-19
• /
• 2017

This study investigated physiological and hematological changes, expression of stress protein Hsp70 mRNA and oxygen consumption in olive flounder (Paralichthys olivaceus) after exposing the fish at different temperature conditions (9, 12, 15, 18 and 21℃) for 24 and 48 hours. Hematological parameters including hematocrit (Ht) and hemoglobin (Hb), cortisol and glucose, aspartate aminotransferase (AST) and alanine aminotransferase (ALT), NH₃, osmolality and total protein (TP) mostly exhibited significant changes at 9 and 12℃. The expression of Hsp70 mRNA was also higher at 9 and 12℃ than at other temperatures. The measured oxygen consumptions were also lower at 9 and 12℃ than at 21℃. It is expected that the study results could be utilized as baseline data to control water temperature during long-distance transportation, e.g. for exporting olive flounder juveniles to overseas.

• The Korean Journal of Air & Space Law and Policy
• /
• v.24 no.1
• /
• pp.91-118
• /
• 2009

In the Republic of Korea, Regional Airlines from Jeju Air and Hansung Airlines have recently entered the domestic market to compete with the existing Legacy Airlines. In addition many of newly established regional low cost carriers like Air Busan, JeanAir, Easter Airline, are preparing to enter the jungle market. These circumstantial changes have come about as transportation competitiveness are getting weak in the market due to simultaneous expansion of surface modes such as a new opening of high-speed rail and extension of highways. The jumbled market entry by regional low cost carriers makes an enormous influence not only in managing transport network of existing carriers but also for the domestic policy of aviation authorities. It is too early to judge whether they would succeed or not. It is necessary to analyze the network operation of these regional carriers launching domestic routes and preparing to launch short distance international routes under the rapid changing market circumstances such as introduction of KTX or decrease in domestic routes by Legacy Airlines. Many regional airlines are to launch the routes connecting Korea-China-Japan, if they could ensure long-haul international routes successfully, it would follow that the difference between Legacy Airlines and Regional Airlines would decrease more and more, which would result in appearance of the $3^{rd}$or $4^{th}$Legacy Airlines The purpose of this study is to analyze the introduction of low cost carriers by regions and economic regional carrier network for non-scheduled air transportation market by taking a look at the regional airlines transportation network in the early stage of the domestic air transport market. For this purpose, cost and profit structure and management effect of transportation cost will be analyzed by comparing the presently operated routes of regional airlines with those of Legacy Airlines. And also demonstrative analysis demanded by the actual market will be achieved through surveys from experts, the actual airlines and travel agencies to build up transportation network.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.4
• /
• pp.543-550
• /
• 2018

The rapid growth of IoT technology induced by the fourth industrial revolution has resulted in research into various types of wireless sensors, and applications based on this technology are prevalent in many areas. However, among the various sites where this technology is used, railway bridges and tunnels with lengths of tens of kilometers have problems with data acquisition, due to the signal noise induced by the long distance measurement and EMI induced by the high voltage power feeding system, when conventional electric sensors are used. To overcome these problems, many studies on fiber optic sensors have been conducted as a substitute for the conventional electric sensors. However, restrictions on the types of fiber optic sensors have limited their application in railways. For this reason, a hybrid measurement system with IoT based wireless data communication, in which both electric and fiber optic sensors can be applied simultaneously, has been developed. In this study, in order to evaluate the applicability of the hybrid measurement system developed in the previous study, a real-time test for 4 types of measurement environments, which reflect possible railway sites, is performed. As a result, it was confirmed that the signals from both the electric and fiber optic sensors, which were acquired at a remote area in real-time, showed good agreement with each other and that this measurement system has the potential to handle sensors with a sampling rate of 2.5 kHz. In the future, it is expected that the IoT-based hybrid measurement system will contribute to the improvement of structural safety by enabling real-time structural health monitoring when applied to various measurement sites.

• Journal of Korean Society of Transportation
• /
• v.21 no.3
• /
• pp.47-56
• /
• 2003

Considering the high density developments along the major traffic corridors in Seoul, transit-oriented street designs will be a very effective to control traffic congestion along the corridors. For testing the effectiveness, we selected. for our case study, Kangnam Street, which is one of the most highly developed corridors in Seoul The traffic study on Kangnam street in 2000 shows that the daily average bus speed is 11.73km/h, which is 5km/h lower than the auto speed. The Central Bus Lane system was applied on the Kangnam street to test impact on bus speed as well as auto speed. Simulation results show that with Central Bus Lane have been improved the travel speeds of bus as well as auto on Kangnam street from 14.4km/hr to 35.0km/hr and from 25.1km/hr to 26.1km/hr, respectively. The bus market share increases about 6-8 percentages. Especially, 13.4% of bus users are increased for long-distance trips.

• Economic and Environmental Geology
• /
• v.54 no.5
• /
• pp.515-533
• /
• 2021

Based on the supply location, demand location, and transportation network, aggregate supply-demand characteristics and aggregate distribution status were analyzed from the results of the closest distance, service areas, and location-allocation scenarios using GIS network analysis. As a result, it was found that the average transport distance of aggregates from the supplier was 6 km on average, the average range of 7 km for sand, and 10 km for gravel was found to reach the destination. In particular, the simulated service area covers about 92% in Seoul-Gyeonggi Province, 85% in Busan-Ulsan-Gyeongnam Province, and more than 90% in Daejeon-Sejong-Chungnam Province. These results have a significant implication in quantitatively interpreting primary data on aggregate supply-demand. Furthermore, these results suggest the possibility of a wide-area quantitative analysis of aggregate supply regions necessary for establishing a basic aggregate plan. The results also evaluated by the site-allocation scenario show that aggregate supply may be possible through companies less than 200 with large-amounts quarries, which is the 700 companies currently supplying small amounts of aggregates on the country. Therefore, in terms of distribution of aggregates, a policy approach is needed to form an appropriate market for regions with high and low density of aggregate supply services, and the necessity of regional distribution and re-evaluation is suggested through an aggregate supply analysis demand across the country. Furthermore, in analyzing the supply-demand network for the aggregate market, additional research is needed to establish long-term policies for the aggregate industry and related industries.

• Journal of the Korean Geographical Society
• /
• v.28 no.1
• /
• pp.40-57
• /
• 1993

This paper aims to show the various aspects of migration in Kwangju merropolitan area, southwestern Korea, for a period of years 1980-1985. Migratory patterns are spatially extensive in countryside around Kwanfju, and due to high accessibility to the metropolitan area urban implosion emerges in the city. In Chonnam province where Kwangju is loca-ted, all cities and counties except for such in-dustrial areas as Yochon, and Kwangyang are experiencing population losses in terms of net migration by survival rate methods. Kwangju is the exceptionally one of in-migration areas in Chonnam, though its central part(Dong-Gu) is also an out-migrated area. Predominantly in-migration urban areas have high proportions of a student age group between 15-19 years, and that reflects the importance of the educational factor in migration analysis. The municipal authorities of Kwangju are planning to block the way of the middle sxhool students who live in the outskirts of Kwangju to entrance to high school in the city. Thant may stir up migrations into Kwangju for the elementary and middle school students, because the city id expected to provide educational opportunities higher and better than remaining Chonnam areas. Population of Kwangju would, therefore, grow as the students migrate into the city. The findings on the residential intra-city movement in selected 5 Dongs indicate that implications of a short-distance movement re noteworthy; neighbour to neighbour, and the nearest stop in the way from the outer Kwangju as well. Trends in a short-distance movement are in accord with Ravensteins's "law of migra-tion". But in casw of the inter-provincial migra-tion to Kwangju, the number of in-migrants from remoter Seoul is more than that from nearer Chonbuk province. Therefore it supports the fact that the movement between capital region and far off local cities overcomes a distance barrier. The temporary mobility for a day has been increased as the standard of living has improved and it reaches a peak on weekend or on con-secutive holidays. The number of temporal movers to Kwangju from capital region and Yongnam area, southeastern Korea has a greatincrease in terms of the frequency of the passengers' mobility, in particular on Myongjol(the ethnic and traditional festival day) in com-parison with on weekdays. By comparison with two largest Myongjols, the number of movers is more on Chusok(The Full Moon festival on lunar August) than on Sol (lunar new year's day). Annual peak point of weekday movers appears in August because of summer vacation. But the lowest one appears in June, which is related to the busy farming season. A patients' move for medical services in on the increase with a change of living conditions. It is especially true in the industrial counties such as Kwangyang and Yochon. By way of conclusion, it should be pointed out that one of the problems we face in survey of migration volume by the survival rate method is that the survival rate somtimes exceeds the value 1.0, in normal states of which should be under 1.0. it may be due to the shortcoming from the census statistics. We should not give therefore too much stress on the importance of migrations or moves as an element of changes in spatial pattern. In cinclusion, the results of the study show some geographic facts as the followings: 1. One of the outstanding phenomena in all types of movement is the seletivity of ages. The most important factors are related to education and employment. 2. Short-distance movement is carried out in accordance with Ravenstein's law, but in case long-distance movement, in-migration from capital region is prominent in spite of remoten-ces. The gravity between large cities such as Kwangju and Seoul, which has a frequent human movenent, causes urban implosion of small cities between those cities. 3. The temporary mobility for a day, in con-trast to that of permanent movement, is more related to transportation, and its volumes and annual variations are a large-scale. 4. Passengers' mobility is high in industrial cities. And the scope of patients' mobility is narrower than passengers'.