• International Journal of Highway Engineering
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• v.11 no.3
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• pp.111-120
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• 2009

Recently, pay adjustment regulation (PAR) has been developed to induce better performing road pavements around the country. This regulation was successfully applied during rehabilitation of highway flexible pavements for the first time, and their results are the focus of this paper. For highway pavements, a lot has been defined by typical amount of works a day. This lot was further divided into several sublots depending on field conditions. According to AASHTO Quality Assurance Guide Specification, pay factors for each lot were statistically determined with field measurements of five performance indicators. And composite pay factors were calculated by accounting for the impact of individual performance indicators on a long-term performance of pavement. In 2008, the PAR was tested with asphalt overlays conducted at all six local headquarters of Korea Expressway Corporation. Also, concerns raised during implementation are discussed in this paper. Limited data used in this study showed that if all performance indicators fall within the construction limits with less variances final construction costs may increase by 50%, whereas 10% reduction in construction costs could be necessary if key performance indicators such as density do not meet the construction quality requirements.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.6
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• pp.203-213
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• 2021

A vehicle crash occurs due to various factors such as the geometry of the road section, traffic, and driver characteristics. A safety performance function has been used in many studies to estimate the relationship between vehicle crash and road factors statistically. And depends on the purpose of the analysis, various characteristic variables have been used. And various characteristic variables have been used in the studies depending on the purpose of analysis. The existing domestic studies generally reflect the average characteristics of the sections by quantifying the traffic volume in macro aggregate units such as the ADT, but this has a limitation that it cannot reflect the real-time changing traffic characteristics. Therefore, the need for research on effective aggregation units that can flexibly reflect the characteristics of the traffic environment arises. In this paper, we develop a safety performance function that can reflect the traffic characteristics in detail with an aggregate unit for one hour in addition to the daily model used in the previous studies. As part of the present study, we also perform a comparison and evaluation between models. The safety performance function for daily and hourly units is developed using a negative binomial regression model with the number of accidents as a dependent variable. In addition, the optimal negative binomial regression model for each of the hourly and daily models was selected, and their prediction performances were compared. The model and evaluation results presented in this paper can be used to determine the risk factors for accidents in the highway section considering the dynamic characteristics. In addition, the model and evaluation results can also be used as the basis for evaluating the availability and transferability of the hourly model.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.3-5
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• 2007

본 논문에서는 새로운 내용기반 이미지 검색 기법으로 식물 잎의 윤곽선에 대하여 동적 시간 정합 기법을 이용하여 유사한 이미지를 효과적으로 검색하는 방법을 제안한다. 이를 위하여 우선 식물 잎의 기준점에 대하여 잎의 가장자리를 따라 가면서 구해지는 거리의 곡선을 통하여 잎의 외형 특성을 표현하였다. 추출된 곡선 정보의 효율적인 저장과 처리를 위하여 곡선의 특성을 표현할 수 있는 퓨리에 계수(Fourier Coefficients)를 계산하고 이를 바탕으로 유사한 이미지를 계산하였다. 이런 과정에서 생기는 문제점으로는 복잡한 형태의 곡선에 대해서는 퓨리에 계수를 통하여 저장하고 복원하는 과정에서 원본 곡선의 세부적인 형태 정보를 상실하게 된다. 이러한 문제를 해결하기 위해서는 복잡한 곡선 유형에 대해서는 복원시 상실되는 정보가 최소화될 수 있는 작은 단위의 구간으로 나누고 이에 대한 퓨리에 계수를 계산하는 방법으로 다수의 퓨리에 계수 세트를 추출하는 이진 구간 분할 (Binary Range Reduction) 알고리즘을 사용하였고 질의 이미지와 저장된 이미지들을 비교하는 과정에서 검색의 정확도를 향상시키기 위하여 동적 시간 정합(Dynamic Time Warping) 알고리즘을 사용하였다. 그리고 검색의 효율을 더욱 높이기 위하여 추출된 외형 정보를 기반으로 잎의 유형을 다양한 카테고리로 분류하는 외형 기형 기반의 잎 분류 기법을 제안하였다. 다양한 실험을 통하여 제안한 기법이 식물 잎 검색에 우수한 성능을 나타냄을 보인다.

• Journal of Broadcast Engineering
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• v.20 no.4
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• pp.521-532
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• 2015

This paper presents a piecewise image denoising with multi-scale block region detector based on quadtree structure for effective image restoration. Proposed piecewise image denoising method suggests multi-scale block region detector (MBRD) by dividing whole pixels of a noisy image into three parts, with regional characteristics: strong variation region, weak variation region, and flat region. These regions are classified according to total pixels variation between multi-scale blocks and are applied principal component analysis with local pixel grouping, bilateral filtering, and structure-preserving image decomposition operator called relative total variation. The performance of proposed method is evaluated by Experimental results. we can observe that region detection results generated by the detector seems to be well classified along the characteristics of regions. In addition, the piecewise image denoising provides the positive gain with regard to PSNR performance. In the visual evaluation, details and edges are preserved efficiently over the each region; therefore, the proposed method effectively reduces the noise and it proves that it improves the performance of denoising by the restoration process according to the region characteristics.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5B
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• pp.489-499
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• 2006

The Potential Flood Damage (PFD) is widely used for representing the degree of potential of flood damage. However, this cannot be related with the design frequency of river basin and so we have difficulty in the use of water resources field. Therefore, in this study, the concept of Potential Risk for Flood Damage Occurrence (PRFD) was introduced and estimated, which can be related to the design frequency. The PRFD has three important elements of hazard, exposure, and vulnerability. The hazard means a probability of occurrence of flood event, the exposure represents the degree that the property is exposed in the flood hazard, and the vulnerability represents the degree of weakness of the measures for flood prevention. Those elements were devided into some sub-elements. The hazard is explained by the frequency based rainfall, the exposure has two sub-elements which are population density and official land price, and the vulnerability has two sub-elements which are undevelopedness index and ability of flood defence. Each sub-elements are estimated and the estimated values are rearranged in the range of 0 to 100. The Analytic Hierarchy Process (AHP) is also applied to determine weighting coefficients in the equation of PRFD. The PRFD for the Anyang river basin and the design frequency are estimated by using the maximum rainfall. The existing design frequency for Anyang river basin is in the range of 50 to 200. And the design frequency estimation result of PRFD of this study is in the range of 110 to 130. Therefore, the developed method for the estimation of PRFD and the design frequency for the administrative districts are used and the method for the watershed and the river channel are to be applied in the future study.

• 한국사회정책
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• v.24 no.1
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• pp.1-31
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• 2017

This paper attempts to analyze citizens' giving behavior by household income level. Particularly, it focuses on participation and amount of secular giving by using 'Social Survey'in 2011, 2013, and 2015 from the Bureau of Statistics and employing Heckman selection model for statistical analysis. This study shows that citizens' participation has a proportional tendency by their income level. Similar to participation of secular giving, citizens' giving amount has also a proportional tendency by their income level. However, the degree of proportional tendency seems not to be significant in the case of amount of secular giving. This empirical analysis promotes understanding of participation and amount of secular giving by citizens' income section in Korea by showing the differences. This paper provides meaningful empirical understanding regarding citizens' secular giving behavior by their income level. In addition, it offers important clues to motivate relevant prospective studies and develop social agenda which contribute to strengthening giving culture in Korea.

• Journal of Biosystems Engineering
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• v.4 no.1
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• pp.24-34
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• 1979

현재 실용테라스 (Terrace) 축조비용의 추정은 단위 테라스장이나 이동토양의 단가에 근거하고 있다. 그런, 근래 l국의 옥수수 지대 (corn belt)에서 널리 이용되고 있는 평행형 테라스의 경우 각 지점마다 성토 및 절토양이 다르기 때문에 이들 방법은 적합하지 않다. 이들 테라스의 경우 테라스장을 따라 토양의 이동이 불가피하므로 차륜형 자적식 스크레이퍼(scraper)가 테라스 축조에 널리 사용되고 있다. 본연구의 목적은 테라스 축조기계의 운행거리에 근거하여 테라스 축조시의 토공비용을 추정하기 위한 새로운 방법을 개발하는데 있었다. 테라스 축조시 토공작업은 전적으로 스크레이퍼에 의해서 , 그리고 테라스 경호장의 마무리 작업은 모트그레이터 (motor grader )에 의하여 수행되는 것을 가정하였다. 이들 기계의 세부적인 수행동작은 테라스 각지점에서의 절토와 성토량 및 이들 토양의 처리를 디지털 컴퓨터(digital computer)를 이용하므로서 계산할 수 있었다. 또한 테라스 축조에 소요되는 토양은 전적으로 테라스 수로부문에서 절취하는 것으로 가정하였다. (즉, 테라스 전장의 총절토양 과 총성토양은 같음) 연구결과 다음과 같은 결론을 얻었다. 1. 성토 및 절토양이 균형된 테라스에 있어서는 스크레이퍼의 운행거리에 근거하여 토공비용을 추정할 수 있는 방법의 개발이 가능하다. 2. 스크레이퍼의 수행구간, 회수 및 토공비용을 결정하기 위해서는 컴퓨터 방법을 이용하는 것이 필요하다. 3. 새로운 컴퓨터 모델은 예시의 테라스에 적용한 결과 테라스 토공비용을 추정하는 데 적합함을 보여주었다. 4. 이 방법은 테라스 축조에 있어서 효율적인 스크레이퍼의 적용에 지침이 될 수 있다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5D
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• pp.587-595
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• 2008

Many studies on bus scheduling optimization have been done from the 1960s to recent years for establishing rational bus schedule plan that can improve convenience of bus passengers and minimize unnecessary runs. After 2000, as part of the Intelligent Transport Systems (ITS), the importance of the schedule management and providing schedule information through bus schedule optimization has become a big issue, and much research is being done to develop optimization models that will increase bus passenger convenience and, on the side of bus management, minimize unnecessary bus operation. The purpose of this study is to calculate the optimal bus frequency and create a timetable for each bus stop by applying DTR or DTRC model that use data for each bus stop and route segment. Model verification process was implemented using data collected from bus management system (BMS) and integrated transit-fare card system for bus route of Seoul's No. 472 line. In order to evaluate the reliability and uncertainty of optimal solution, sensitivity analysis was implemented for the various parameters and assumptions used in the bus scheduling model.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.3
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• pp.127-134
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• 2016

Land suitability assessment for apples and pears was conducted with soil and climate information in South Korea. In doing so, we intended to preserve land and increase the productivity by providing valuable information regarding where more suitable areas for apples or pears are located. We used soil classification driven by soil environmental information system developed by National Institute of Agricultural Science, RDA, and also used climate classification in digital agro-climate map database for which is made by National Institute of Horticultural and Herbal Science. We combined both soil and climate classification results using a most-limiting characteristic method. The combined results showed very similar patterns with the results by classification based on soil information. Such results seem to come from the fact that the classification results by soil relatively lower than those by climate information. The results by soil classification seem to be too downgraded and checking if the final classification ranges in soil are reasonably made is strongly required. Although the most limiting characteristic method had been used widely in land suitability assessment, adapting the method based on results by soil and climate can be influenced by one downgraded factor. Therefore, alternative ways should be carefully considered for increasing the accuracy.

• Korean Journal of Environment and Ecology
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• v.27 no.6
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• pp.777-793
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• 2013

The purpose of this study is to provide the basic reference for appropriate ecological park planning through investigation and analysis of inviting environment of Suncheon Bay Ecological Park within the framework of 'universal design'. For this, investigating items were selected through literature reviews and legal standard of ecological park suggested by laws. Field survey on Suncheon Bay Ecological Park was conducted, The results suggesting analytical and practical implications are as follows. First, guided handles of any facilities were not equipped, so urgent supplementation is needed with legal standard of universal design. Especially, detailed criterion of universal design focusing on visitors' convenience should be reflected. Second, all facilities for the blind were not equipped and the floor height of entrance was also unsuitable. It implies that the disabled and the senior are restrained from doing independent activity, therefore, appropriate standard focusing on 'universal design' for the wide open activity space such as the park area should be re-provided. Finally, guidelines for applicable universal design of the activity space for the experience on the ecological park should be re-established.