• Title/Summary/Keyword: air transportation

Search Result 1,134, Processing Time 0.023 seconds

Statistical Models of Air Temperatures in Seoul (서울시 도시기온 변화에 관한 모델 연구)

  • 김학열;김운수
    • Journal of the Korean Institute of Landscape Architecture
    • /
    • v.31 no.3
    • /
    • pp.74-82
    • /
    • 2003
  • Under the assumption that the temperature of one location is closely related to land use characteristics around that location, this study is carried out to assess the impact of urban land use patterns on air temperature. In order to investigate the relationship, GIS techniques and statistical analyses are utilized, after spatially connecting urban land use data in Seoul Metropolitan Area with atmospheric data observed at Automatic Weather Stations (AWS). The research method is as follows: (1) To find out important land use factors on temperature, simple linear regressions for a specific time period (pilot study) are conducted with urban land use characteristics, (2) To make a final model, multiple regressions are carried out with those factors and, (3) To verify that the final model could be appled to explain temperature variations beyond the period, the model is extensively used for 5 different time periods: 1999 as a whole; summer in 1999; 1998 as a whole; summer in 1998; August in 1998. The results of simple linear regression models in the pilot study show that transportation facilities and open space area are very influential on urban air temperature variations, which explain 66 and 61 percent of the variations, respectively. However, the other land use variables (residential, commercial, and mixed land use) are found to have weak or insignificant relationship to the air temperatures. Multiple linear regression with the two important variables in the pilot study is estimated, which shows that the model explains 75 percent of the variability in air temperatures with correct signs of regression coefficients. Thus, it is empirically shown that an increase in open space and a decrease in transportation facilities area can leads to the decrease in air temperature. After the final model is extensively applied to the 5 different time periods, the estimated models explain 68 ∼ 75 percent of the variations in the temperatures is significant regression coefficients for all explanatory variables. This result provides a possibility that one air temperature model for a specific time period could be a good model for other time periods near to the period. The important implications of this result to lessen high air temperature we: (1) to expand and to conserve open space and (2) to control transportation-related factors such as transportation facilities area, road pavement and traffic congestion.

Simulation and Cost Estimation of Energy Transportation at Ambient Temperature Using an Absorption System (흡수식을 이용한 상온에너지수송의 모사 및 비용평가)

  • 김성수;오민규;전상현;강용태
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.15 no.12
    • /
    • pp.1028-1034
    • /
    • 2003
  • The objectives of this paper are to study the effect of key parameters on the cycle performance and capacity and to estimate the cost of latent and sensible energy transportation systems. The overall conductance (UA) of each component, the ambient temperature and the absorber inlet temperature are considered the key parameters. It is concluded that COP of the solution transportation using an absorption system (STA) at ambient temperature is 10% higher than that of the conventional sensible system. It is also found that the cost of STA system can be reduced 7.5 times to that of sensible energy transportation for one year of operation with 10 km transportation distance.

Life-Cycle Cost Analysis of Solution Transportation Absorption System (LCC 분석에 의한 상온 에너지수송용 흡수식 냉동기(STA)의 경제성 평가)

  • 오민규;이봉진;홍희기;강용태
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.16 no.6
    • /
    • pp.506-513
    • /
    • 2004
  • The objective of this paper is to evaluate the economic performance of latent and sensible energy transportation systems. LCC (Life-Cycle Cost) analysis is a practical method and a guideline for evaluating the economic performance of considered systems during the Life-Cycle Period. By comparing the LCC of alternatives, The most ideal alternative is determined which has the lowest LCC. It is concluded that the cost of STA (Solution Transportation Absorption system) can be reduced by 67% to that of sensible energy transportation for study period with 10 km transportation distance.

A Study on the Risk Assessment in LPG Transportation by Tank Lorry (LPG 탱크로리 수송중 위험성 평가에 관한 연구)

  • 이재준;김윤화;윤성렬;엄성인;백종배;고재욱
    • Journal of the Korean Society of Safety
    • /
    • v.12 no.4
    • /
    • pp.86-92
    • /
    • 1997
  • Demand of LPG and LNG will increase continuously due to high calories, clearness, and convenience for usage. These gases are used widely for power plants, industrial plants, and domestic fuel. But accidents related with gas are increasing in proportion to increment of gas usage. Especially LPG has high ignitability due to weak dispersion to air and accumulation at low place because LPG is heavier than air. There are many hazards during transportation as well as production, storage, and usage of LPG. Commonly, tank lorry is used for inland transportation of LPG. If tank lorry were to raise leakage incidents and then LPG released during transporting, the accidents cause serious effects on the environment as well as human damage of surrounding area. In this study, therefore, hazards which cause LPG of tank lorry to leak during transportation were identified and risk of LPG transportation was assessed quantitatively. Also, the result of this study might be a useful measure for predicting damage and preparing safe transportation strategies of LPG tank lorry.

  • PDF

Outbound Air Travel Demand Forecasting Model with Unobserved Regional Characteristics (미관찰 지역 특성을 고려한 내국인 국제선 항공수요 추정 모형)

  • YU, Jeong Whon;CHOI, Jung Yoon
    • Journal of Korean Society of Transportation
    • /
    • v.36 no.2
    • /
    • pp.141-154
    • /
    • 2018
  • In order to meet the ever-increasing demand for international air travel, several plans are underway to open new airports and expand existing provincial airports. However, existing air demand forecasts have been based on the total air demand in Korea or the air demand among major cities. There is not much forecast of regional air demand considering local characteristics. In this study, the outbound air travel demand in the southeastern region of Korea was analyzed and the fixed-effects model using panel data was proposed as an optimal model that can reflect the inherent characteristics of metropolitan areas which are difficult to observe in reality. The results of model validation show that panel data analysis effectively addresses the spurious regression and unobserved heterogeneity that are difficult to handle in a model using only a few macroeconomic indicators with time series characteristics. Various statistical validation and conformance tests suggest that the fixed-effects model proposed in this study is superior to other econometric models in predicting demand for international demand in the southeastern region.

An Empirical Study on the Forwarder's Satisfaction to Service Quality (해공복합운송 서비스품질이 포워더의 만족에 미치는 영향)

  • Choi, Dong-Oh
    • Journal of Korea Port Economic Association
    • /
    • v.28 no.2
    • /
    • pp.195-211
    • /
    • 2012
  • As the globalisation of corporate's managemental environment, all parts of logistics such as procurement, production and sales are globalized. The ways of transportation in Korea and Japan, where are difficult to use land-transportation, are sea-transportation and air-transportation. Sea & air is a way of the international transportation which is combined by Sea and Air to reduce the transportation fee and shorten the delivery time. The main body of multimodal transportation service is the corporate, actual carrier who undertakes the actual transport. It is essential to establish service quality to maintain their going concern. In other words, the actual carrier has to emphasize the importance of service quality to forwarder tan any other business conditions. In this study, we examine the determinants of service quality for actual carrier in multimodal transportation. Through the multi-regression analysis based on SERVPERF by Cronin and Taylor (1992), we analyze the service quality dimensions of actual carrier. Also we examine the relations between the determinants and customer's satisfaction. Using statistical hypothesis testing, the determinants of service quality are reliability, responsiveness, assurance, tangibles, and we could look into the factors which the actual carrier should control with priority.

A Study on a development plan for multi-transportation in Incheon: Focused on Incheon and main cities in Northern China (인천지역의 복합운송체계별 발전방안 연구 - 인천과 상해이북지역 중심으로 -)

  • Chung, Tae-Won
    • Journal of Korea Port Economic Association
    • /
    • v.26 no.1
    • /
    • pp.259-276
    • /
    • 2010
  • This study shows how Incheon will advance into roadmap as multi-transport hub in Northeast Asia hereafter and be proposed an urgent tasks and roles to construct a multi-transportation system for Incheon, which has both an international airport and port. The multi-transportation point of view of inter-major cities competitiveness of total scores was proposed 1. Shanghai(64.8 points), 2 in Hongkong(64.5), 3 in Incheon(62.9), and 4 in Busan(60.4) and Incheon was estimated to have enough competitiveness to be the international multi-transport hub in Northeast Asia. Sea & Air transportation revealed the most important multi-transportation in the Incheon region. In conclusion, this research suggests a development plan for multi-transportation in Incheon. Firstly, it proposes construction of sea & air transportation distribution center and agreement that simplifies logistic process between Incheon and Tianjin, secondly, suggests to activate project for the purpose of creating a better sea-land transportation system between Incheon and Shanghai.