• Korean Journal of Hydrosciences
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• 제8권
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• pp.85-95
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• 1997

The multiple flow direction algorithm to calculate the spatial variation of the saturation tendency, I. e. topographic index, is integrated into the Geographic Information System, GRASS. A procedure is suggested to consider the effect of a tile system on calculating the topographic index. A small agricultural subwatershed ($3.4\;\textrm{km}^2$) is used for this study. The impact of a tile system on the groundwater table can be effectively considered by the Laplace's equation to the DEM. The analysis shows that a tile system has a high degree of saturation to compared to the case without tile drainage, and the predicted riparian area is well fitted to the actual watershed condition. A procedure is suggested to consider a tile system's effect on calculating the topographic index.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1591-1598
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• 2009

Recently, the researches on the urban regeneration projects have been performed very actively. It is a part of the effort that solves some social and economical problems occurred by deteriorated buildings and degraded infrastructures through new urban regeneration projects or redevelopment projects. However, the urban regeneration projects show the characteristics that can not guarantee in the project performance because the projects have various and complex stakeholders related to these projects and are exposed to lots of risks due to its huge scale. This study proposed the risk performance index method to improve the efficiency of the overall performance measurement for a mega-project by extending from the traditional cost/schedule based performance measurement system. The risk performance index method proposed in this study has a similar system to the EVMS, and makes possible to perform a three dimensional integrated performance measurement in cost/schedule/risk through 18 different indexes that compose the risk performance index.

• Geomechanics and Engineering
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• 제4권3호
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• pp.219-227
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• 2012

Pavement management systems require systematic monitoring of pavement surfaces to determine preventive and corrective maintenance. The process involves the accumulation of large amounts of visual data, typically obtained from site visitation. The pavement surface condition is then correlated to a pavement distress index that is based on a scoring system previously established by state or federal agencies. The scoring system determines if the pavement section requires maintenance, overlay or reconstruction. One of the surface distresses forming part of the overall pavement distress index is the Alligator Crack Index (AC Index). The AC Index involves the visual evaluation of the crack severity of a section of a pavement as being low, medium, or high. This evaluation is then integrated into a formula in order to obtain the AC Index. In this study a quantification of the visual evaluation of the severity of alligator cracking is carried out using photographs and the fractal dimension concept from fractal theory. Pavements with low levels of cracking were found to have a fractal dimension equal to 1.051. Pavements with moderate levels of cracking had a fractal dimension equal to 1.1754. Pavements with high degrees of cracking had a fractal dimension that varied between 1.5037 (high) and 1.7111 (very high). Pavements with a level of cracking equal to 1.8976 represented pavements that disintegrated and developed potholes. Thus, the visual evaluation of the state of cracking of a pavement (the AC Index) could be enhanced with the use of the fractal dimension concept from fractal theory.

• The Journal of Asian Finance, Economics and Business
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• 제7권8호
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• pp.197-204
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• 2020

Nowadays, many construction engineering and technology enterprises are evolving to find that prosperity is driven and inspired by an open economy with dynamic markets and fierce multifaceted competition. Besides brand and product uniqueness, the ability to quickly provide customers with quotes are matters of concern. Such a requirement for prompt cost estimation of construction investment projects with the use of a construction price index poses a significant challenge to contractors. This is because the nature of the construction industry is shaped by changes in domestic and foreign economic factors, socio-financial issues, and is under the influence of various micro and macro factors. This paper presents a fuzzy decision-making approach for calculating critical factors that affect the construction price index. A qualitative approach was implemented based on in-depth interviews of experts in the construction industry in Vietnam. A synthetic comparison matrix was calculated using Buckley approach. The CoA approach was applied to defuzzified the fuzzy weights of factors that affect the construction price index. The research results show that the top five critical factors affecting the construction price index in Vietnam are (1) consumer price index, (2) gross domestic product, (3) basic interest rate, (4) foreign exchange rate, and (5) total export and import.

• 대한기계학회논문집A
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• 제36권12호
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• pp.1503-1510
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• 2012

본 논문은 종/횡방향 충돌 회피 시스템의 통합을 통한 통합 위험 관리 시스템 (IRMS) 에 대하여 기술하였다. 이를 위하여 종/횡방향 충돌 위험을 나타낼 수 있는 지표가 개발되었으며, 이를 통하여 통합 제어 전략을 구성하였다. 충돌 회피 제어를 위하여 운전자-제어기-차량 시스템에 대한 선형 모델을 구성, 이를 바탕으로 운전자-제어기간 협력을 통한 충돌 회피 제어 알고리듬을 개발하였다. 개발된 통합 위험 관리 시스템은 차량 동역학 모의 시험 프로그램인 CARSIM 과 MATLAB/Simulink 를 연동, 모의시험을 통하여 성능을 확인하였다.

• Current Optics and Photonics
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• 제5권6호
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• pp.606-616
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• 2021

A photonic integrated interferometric imaging system possesses the characteristics of small-scale, low weight, low power consumption, and better image quality. It has potential application for replacing conventional large space telescopes. In this paper, the principle of photonic integrated interferometric imaging is investigated. A novel lenslet array arrangement and lenslet pairing approach are proposed, which are helpful in improving spatial frequency coverage. For the novel lenslet array arrangement, two short interference arms were evenly distributed between two adjacent long interference arms. Each lenslet in the array would be paired twice through the novel lenslet pairing approach. Moreover, the image reconstruction model for optical interferometric imaging based on compressed sensing was established. Image simulation results show that the peak signal to noise ratio (PSNR) of the reconstructed image based on compressive sensing is about 10 dB higher than that of the direct restored image. Meanwhile, the normalized mean square error (NMSE) of the direct restored image is approximately 0.38 higher than that of the reconstructed image. Structural similarity index measure (SSIM) of the reconstructed image based on compressed sensing is about 0.33 higher than that of the direct restored image. The increased spatial frequency coverage and image reconstruction approach jointly contribute to better image quality of the photonic integrated interferometric imaging system.

• 대한토목학회논문집
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• 제28권1D호
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• pp.1-10
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• 2008

최근 서울시는 TOD 기법을 활용하여 도심을 재활성화하기 위한 대규모 사업을 추진하고 있다. 그런데 TOD형 개발은 고밀개발을 전제로 하기 때문에 교통혼잡이나 환경의 질에 영향을 끼친다. 본 논문의 목적은 도로 뿐 아니라 버스, 지하철 등의 용량을 함께 고려한 통합교통서비스지표를 개발하여 TOD 개발을 촉진하는데 있다. 이를 위해 외국사례를 검토하고, 새로운 통합교통서비스 지표를 개발하고 이를 활용하여 서울시 도심에서 TOD형 고밀개발이 일어났을 때 교통부분의 기대효과를 분석하였다. 본 연구에서 개발한 통합교통서비스지표는 승용차, 택시, 버스로 구성된 도로서비스환경지표와, 지하철서비스환경 지표로 구성되며, 두 개의 지표를 통합하는 방법은 각 교통죤별 서비스환경에 각 죤별 수단분담률로 가중평균해서 계산하되, 각 수단분담률의 합은 1로 하였다. 이러한 통합교통서비스환경(ITLOS: Integrated Transportation Level Of Service)의 수치는 0에서 1사이의 값을 가지게 되며, 0에 가까울수록 개발에 필요한 교통여건이 좋은 것으로 해석된다. 본 연구에서 도심고밀개발에 따른 기대효과를 분석하기 위해 대중교통과 도로교통을 동시에 고려한 통합교통서비스지표와 도로교통서비스 수준만을 고려하는 통행속도 지표를 활용했다. 두 지표 모두 도심 고밀 개발 시 교통서비스 수준은 악화되는 것으로 나타났고 서울시 전체의 교통서비스 수준은 개선되는 것으로 분석되었다. 하지만 통합교통서비스 지표를 사용할 경우 비율적으로 도심교통상황의 악화 정도는 평균속도지표의 경우에 비해 낮게 나타났고, 반면 서울시 전체적인 개선폭은 비율적으로 상당히 높게 분석되었다.

• 환경영향평가
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• 제20권3호
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• pp.367-379
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• 2011

This study was conducted to develop an ecological park planning model to enhance the functions of habitats and ecological corridors in Green Belt Areas, because changing policies have resulted in the degredation of the Green Belts due to progressive fragmentation of ecosystems. The principal outcome of the study is to plan an ecological park model through the restoration of habitats. In order to evaluate the capacity of the model to enhance the ecological functions of habitats and ecological corridors in Green Belt Areas, a simulation of habitats was carried out in the Sungnam-Yusoo region. The model was developed via following steps: 1. Selection of candidate sites and selection of the study site by analyzing development factors; 2. Selection of target species that can represent the habitat at the site; 3. Analysis of the site's suitability index for the target species; 4. Establishment of a conceptual plan to enhance and expand the currently produced suitability index; 5. Creation of a master plan based on the conceptual plan; and 6. Evaluation of the enhanced and expanded suitability index of the site. The study showed that the Habitat Unit (HU) of Rana coreana, which was selected as the target species of the study, increased from $28,044m^2$(3.6%) to $224,352m^2$(28.8%), and the HU of the site as the ecological corridor for wild animals increased from $4,674m^2$(0.6%) to $152,684m^2$(19.6%). The study results show that the ecological deficits of the Green Belt Area can be overcome by enhancing the ecological functions of the region, which should be beneficial. The model could be utilized for effective enhancement and management of other Green Belt Areas.

• Smart Structures and Systems
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• 제15권1호
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• pp.1-13
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• 2015

This paper proposes an analytical mode decomposition (AMD) and Hilbert transform method for structural nonlinearity quantification and damage detection under earthquake loads. The measured structural response is first decomposed into several intrinsic mode functions (IMF) using the proposed AMD method. Each IMF is an amplitude modulated-frequency modulated signal with narrow frequency bandwidth. Then, the instantaneous frequencies of the decomposed IMF can be defined with Hilbert transform. However, for a nonlinear structure, the defined instantaneous frequencies from the decomposed IMF are not equal to the instantaneous frequencies of the structure itself. The theoretical derivation in this paper indicates that the instantaneous frequency of the decomposed measured response includes a slowly-varying part which represents the instantaneous frequency of the structure and rapidly-varying part for a nonlinear structure subjected to earthquake excitations. To eliminate the rapidly-varying part effects, the instantaneous frequency is integrated over time duration. Then the degree of nonlinearity index, which represents the damage severity of structure, is defined based on the integrated instantaneous frequency in this paper. A one-story hysteretic nonlinear structure with various earthquake excitations are simulated as numerical examples and the degree of nonlinearity index is obtained. Finally, the degree of nonlinearity index is estimated from the experimental data of a seven-story building under four earthquake excitations. The index values for the building subjected to a low intensity earthquake excitation, two medium intensity earthquake excitations, and a large intensity earthquake excitation are calculated as 12.8%, 23.0%, 23.2%, and 39.5%, respectively.

• 한국의류학회지
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• 제47권5호
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• pp.779-803
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• 2023

The growth of digital news media and the stock price index has resulted in economic fluctuations in the fashion industry. This study examines the impact of fashion industry news and macroeconomic changes on the Textile & Wearing Apparel KOSPI over the past five years. An auto-regressive integrated moving average exogenous time series model was conducted using the fashion industry stock market index, the news topic index, and macro-economic indicators. The results indicated the topics of "Cosmetic business expansion" and "Digital innovation" impacted the Textile & Wearing Apparel KOSPI after one week, and the topics of "Pop-up store," "Entry into the Chinese fashion market," and "Fashion week and trade show" affected it after two weeks. Moreover, the topics of "Cosmetic business expansion" and "Entry into the Chinese fashion market" were statistically significant in the macroeconomic environment. Regarding the effect relation of Textile & Wearing Apparel KOSPI, "Cosmetic business expansion," "Entry into the Chinese fashion market," and consumer price fluctuation showed negative effects, while the private consumption change rate, producer price fluctuation, and unemployment change rate had positive effects. This study analyzes the impact of media framing on fashion industry business cycles and provides practical insights into managing stock market risk for fashion companies.