• Proceedings of the KSR Conference
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• 2010.06a
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• pp.2166-2178
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• 2010

The Korea Transportation Database (KTDB) is used to obtain data on the origin and destination (OD) of inter-city travel, which are currently used in railroad planning when estimating traffic demand. The KTDB employs the trip assignment method, whereby the total traffic volume researched for inter-city travel in Korea is divided into road, rail and air traffic, etc. However, as regards rail travel, the railroad stations are not identical to the existing zones or the connector has not been established because there are several stations in one zone as such, certain problems with the applicable methods have been identified. Therefore, estimates of the volume of railroad traffic using the KTDB display low reliability compared to other modes of transportation. In this study, these problems are reviewed and analyzed, and use of the aggregate model method to estimate the direct demand for rail travel is proposed in order to improve the reliability of estimation. In addition, a method of minimizing error in traffic demand estimation for the railroad field is proposed via an analysis of the relationship between the aggregate model and various social-economic indicators including population, distances, numbers of industrial employees, numbers of automobiles, and the extension of roads between cities.

• Monthly Duck's Village
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• s.81
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• pp.41-44
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• 2010

어느 산업을 불문하고 통계는 산업발전에 기초하며 과거와 현재를 통해 미래의 알려줄 수 있는 나침반과 같은 존재일 것이다. 이에 1조원 시대를 넘어 2조원시대로 성장해가는 오리산업은 통계 부재로 수요예측이나 산업의 경쟁력 향상 등 많은 어려움이 있었으나, 올해부터는 가축동향 및 생산비관련 통계 등에 대한 건의가 수렴되어 차츰 다양한 통계가 나올 것이며 이로써 기초를 더욱 다져가며 성장할 수 있을 것이라 예상된다. 2009년 통계자료는 검역원 및 기타 기관에서 집계되고 있는 자료와 협회에서 추정, 조사된 자료이다.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.114-119
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• 2004

Endbeam is an important structural member of freight bogie for the support of service loading. In general, more than 25 years' durability is necessary. However, endbeam occur fatigue fracture in dynamic stress concentration location because comparatively strength and stiffness are low. Therefore, structure analysis is performed to evaluate structural problem of endbeam and local strain range as durability analysis. The number of cycles is extracted concerning the bogie in operation by measurement dynamic stress time history on critical part which is crack initiation in actual fact. At this time rainflow cycle counting is used to consider change of stress for operating condition. Based on the fatigue life curves and the stress analysis, the fatigue life of the endbeam is predicted and compared with the experimentally determined fatigue life, resulting in a fairly good correlation.

• Journal of Korean Society of Transportation
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• v.26 no.2
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• pp.147-156
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• 2008

It has been widely known that there are so many factors making travel demand errors in transportation forecasting steps. One of the reasons may stem from the level of aggregation of zone and network in analysis process. This paper investigates the effect of level of aggregation considering with number of zones in travel demand forecasting by expanding or reducing the zone and network gradually. Numerical results show that the aggregation could not make a significant impact on the travel demand, while disaggregation does. These results imply that a careful manipulation is required to add or to reduce zones and links in transportation planning process.

• Journal of the Korean Society for Railway
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• v.20 no.2
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• pp.265-274
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• 2017

For accurate demand forecasting of railway logistics, we estimated intercity freight mode choice models based on the binary logit model and using production-consumption data from the Korea Transport Database. We estimated two types of models and compared the results by major item of railway logistics, such as container, cement, and steel: 1) The aggregate freight mode choice models are based on the revealed preference (RP) data and 2) The disaggregate models are based on the stated preference (SP) data. With respect to the container, the travel time variable was found to be statistically significant; however, the travel cost variable was not statistically significant in the RP model, while the travel cost variable was statistically significant in the SP model. For cement and steel, the travel cost variables were statistically significant but the travel time variables were not statistically significant in either the RP or the SP models. These results are inconsistent with results from previous studies based on SP data, which showed that the travel time variables were significant. Consequently, it can be concluded that the travel time factor should be considered in container transport, but that this factor is negligible for cement and steel transport.

• Journal of Korean Society of Transportation
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• v.23 no.2
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• pp.25-36
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• 2005

In this study, we suggested a new approach method forecasting distribution demand of urban rail transit usign fuzzy control, with intend to reflect irregularity and various functional relationship between trip length and distribution demand. To establish fuzzy control model and test this model, the actual trip volume(production, attraction and distribution volume) and trip length (space distance between a departure and arrival station) of Daegu subway line 1 were used. Firstly, usign these data we established a fuzzy control model, nd the estimation accuracy of the model was examined and compared with that of generalized gravity model. The results showed that the fuzzy control model was superior to gravity model in accuracy of estimation. Therefore, wwe found that fuzzy control was able to be applied as a effective method to predict the distribution demand of urban rail transit. Finally, to increase the estimation precision of the model, we expect studies that define membership functions and set up fuzzy rules organized with neural networks.

• Life and Agrochemicals
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• s.278
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• pp.22-25
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• 2012

2011년 우리나라 농약시장은 2010년 보다 생산은 물론 출하도 줄어든 것으로 나타났다. 한국작물보호협회가 최종 집계한 자료에 따르면 2011년도 농약 생산량은 1만7천9백91톤으로 전년도 2만1백66톤 보다 10.8%가 감소했으며 출하량은 1만9천1백60톤으로 전년도 2만4백31톤 보다 9.3%가 감소한 것으로 나타났다. 2008년 이후의 지속적인 감소 추세는 기후변화에 의한 영향과 재배면적의 감소에 의한 것으로 예측된다. 지난해 국내 농약 생산 출하 현황을 작물별, 약제별, 제형별로 자세히 알아본다.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.137.2-137.2
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• 2005

• Proceedings of the Korean System Dynamics Society
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• 2002.08a
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• pp.1-26
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• 2002

우리나라 자동차 보급률은 자동차 1 대당 인구 3.9명으로 집계되고 있다. 이 수치는 미국(1.3명), 일본(1.8명), 서유럽(평균 2.1명) 등에 비해 아직 차이가 많으나, 우리나라의 짧은 자동차 역사를 감안할 때 거의 성숙기에 이른 것으로 볼 수 있다. 자동차 산업면에서도 1980년대 이전 수요가 공급을 초과하는 공금 주도 시장에서 1990년대의 과도기를 거쳐 지금은 공급능력이 수요를 초과하는 수요주도 시장으로 변환되었다.(중략)

• Survey Research
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• v.12 no.1
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• pp.141-152
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• 2011

During major elections, three terrestrial broadcasting stations in Korea have covered the progresses of election results by announcing the simple sum of ballot counts of all ballot counting stations. The current approach, however, does not properly reflect the actual ballot count differences by ballot counting location, leading to cause unnecessary but possible confusions. In addition, the current coverage approach restricts the broadcasters from using regional poll data gained through exit polls by letting them to use the significant information on a one-off purpose to announce the initial prediction of the poll results and to fully disregard the exit poll results during the ballot counting process. Based on the understanding, this paper is designed to suggest a Bayesian approach to consolidate the exit poll results with the progressive ballot counting results and announce them as such. The suggested consolidation approach is expected to mitigate or avoid the possible confusions that may arise in connection with the different ballot counting paces by ballot counting station.