• Structural Engineering and Mechanics
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• v.17 no.3_4
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• pp.409-428
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• 2004

In this paper, a Holder exponent, a measure of the degree to which a signal is differentiable, is presented to detect the presence of a discontinuity and when the discontinuity occurs in a dynamic signal. This discontinuity detection has potential applications to structural health monitoring because discontinuities are often introduced into dynamic response data as a result of certain types of damage. Wavelet transforms are incorporated with the Holder exponent to capture the time varying nature of discontinuities, and a classification procedure is developed to quantify when changes in the Holder exponent are significant. The proposed Holder exponent analysis is applied to various experimental signals to reveal underlying damage causing events from the signals. Signals being analyzed include acceleration response of a mechanical system with a rattling internal part, acceleration signals of a three-story building model with a loosing bolt, and strain records of an in-situ bridge during construction. The experimental results presented in this paper demonstrate that the Holder exponent can be an effective tool for identifying certain types of events that introduce discontinuities into the measured dynamic response data.

• Journal of the Korean Society for Railway
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• v.13 no.3
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• pp.339-348
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• 2010

The government continues to make efforts to improve effectiveness, integration and connectivity of public transportation systems. But there have been only a few studies about it. This paper addresses the quality evaluation of pedestrian facility service in transfer stations at urban railroad. LOS (Level Of Service) model of urban railroad by facility based on the body ellipse and density recalculated considering the recent Korean body standard and the suggested Pedestrian Moving Equivalent (PME) and Pedestrian Waiting Equivalent (PWE). For LOS model for the ticket booths and ticket vending machines, queuing theory has been applied to determine LOS of Pedestrians. And the importance weights among the pedestrian facilities is obtained by applying AHP analysis. Lastly, this paper shows and discusses the evaluation results of overall LOS of pedestrian facilities of five urban railroad transfer stations in Seoul.

• Journal of Aerospace System Engineering
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• v.13 no.5
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• pp.87-93
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• 2019

This study suggests the development of the ALE (Automatic Link Establishment) system for the long-range communication with a helicopter at the lands or marines by HF (High Frequency) radios. In the condition of LOS or more than 35 NM, the communication success rate is significantly lowered when the frequency is manually selected because of the reduced transmission power and various strong RF environment noise signals. In this paper, we make an effort to overcome the difficulties of choosing the optimal frequency when the operating frequency selection is manually operated in long-distance communication or LOS uncertain environment. The ALE system is designed based on the frequency analysis propagation software and is verified that the communication success rate is increased by applying the proposed system. The ALE system was applied to the helicopter system and the ground/flight test was conducted. As a result, the superiority and efficiency of the proposed system were verified.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.671-679
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• 2016

Bridges, which constitute one of the key facilities in a social infrastructure, are easily accessed and used by users, so that keeping their performance above a certain level is essential. According to various cases in the U.S., Japan and Europe with a long construction history, it is expected that the maintenance cost of bridges in Korea will increase continuously in the future, so a rational decision making system based on engineering factors is necessary to optimize the performance of and maintain them by allocating the limited budget efficiently. This study is a preliminary basic study for the purpose of developing a common asset management system for managing all of the bridges and maintaining the level of service provided by them. The scope of this preliminary study is limited to bridges in urban areas. The bridge asset management system for bridges in urban areas, their level of service (LOS) and performance measure (PM) were developed by carrying out a workshop consisting of both experts and stakeholders. The analysis on the weights of the value and performance measure for each performance indicator was carried out by using the multi-attribute utility theory and the AHP method. In order to confirm the application of the weight of the performance measure and value of the performance indicator, six bridges in an example city were selected, LOS analysis was applied and its results were reviewed.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.3
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• pp.34-45
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• 2019

Based on the analysis of congestion conditions in small cities with a population of less than 500,000 in Chungcheong Province, this study conducted a feasibility study on the scope of congestion improvement projects. Further, traffic congestion management standards were further established by analyzing LOS as well as the speed of traffic presented by congestion criteria in the existing Project. According to the analysis according to the congestion management standard LOS suggested in this study, Asan city has the most major number of highways where LOS E occurs for more than 3 hours, followed by Sejong City and Gongju City. In addition, when comparing the ratio of the busy main roads according to the frequency of LOS E by city size, it was analyzed that the ratio and extension of the busy highways relative to the overall extension of the large Chungcheong area are similar to the ratio in small cities in the Chungcheong region. Therefore, traffic congestion occurred in small cities and the feasibility of the improvement project was revealed.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.1115-1119
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• 2013

Background: Febrile neutropenia (FN) is a serious complication following chemotherapy and is associated with significant mortality and financial expenditure. The aim of this study was to evaluate risk factors for longer length of stay (LOS) and mortality and cost of treatment among hospitalized adults with cancer who developed febrile neutropenia in Thailand. Materials and Methods: Information on illness of inpatients and casualties came from hospitals nationwide and from hospital withdrawals from the 3 health insurance schemes in fiscal 2010. The data covered 96% of the population and were analyzed by age groups, hospital level, and insurance year schemes in patients with febrile neutropenia. Results: A total of 5,809 patients were identified in the study. The mortality rate was 14%. The median LOS was 8.67 days and 69% of patients stayed for longer than 5 days. On bivariate analysis, age, cancer type, and infectious complications (bacteremia/sepsis, hypotension, fungal infections, and pneumonia) were significantly associated with longer LOS and death. On multivariate analysis, acute leukemia and infectious complications were linked with longer LOS and death significantly. The median cost of hospitalized FN was THB 33,686 (USD 1,122) with the highest cost observed in acute leukemia patients. Conclusions: FN in adult patients results in significant mortality in hospitalized Thai patients. Factors associated with increased mortality include older age (>70), acute leukemia, comorbidity, and infectious complications.

• Proceedings of the KOR-KST Conference
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• 1998.02a
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• pp.39-73
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• 1998

• Proceedings of the Korea Water Resources Association Conference
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• 1995.05a
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• pp.228-237
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• 1995

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.2
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• pp.55-61
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• 2012

The primary factors of the LOS(Line-of-Sight) analysis process are terrain height, camera capacity, and canopy cover. The canopy cover rate differs depending on the changing season, and its value is influenced by the tree density, tree height, and etc. This study generated the canopy cover value based on relationship between NDVI(Normalized Difference Vegetation Index) and DMT(Density Measure % of Tree/Canopy Cover), which is a digital map attribute, and then performed the LOS analysis on six station of test sites. As results, It was found that NDVI and DMT are correlated with each other through the experiments. Based on this finding, new DMT map can be generated using NDVI. Also, There is a difference between the result of visibility analysis using the present DMT and one using a new DMT. Especially, the spatial distributions of the detected visible areas are significantly different between the two visibility analysis results.

• Journal of Korean Society of Transportation
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• v.24 no.3 s.89
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• pp.63-71
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• 2006

There were many theories to suggest the indicators that evaluate stability and reflect the plan in mixed traffic street in all traffic modes This Paper analyzed residential street of Suwon City adopting time-space occupancy index among these indicates. Three survey street. congregated into apartment house. were selected to analyze this and pictured by video camera over one hour. and the length of these street were 76m, 55m, and 34m each, and major street by each region, comparably high in Pedestrians and pass vehicles, were selected. Basic datum to calculate time-space occupancy index and time-space occupancy index per person was gathered through video analysis. i.e Parameters for pedestrians, cars, bicycles, average speed of bicycles, and parking car. There are some limitation to analyze LOS of mixed traffic street in all traffic modes, not pedestrian mall. Therefore this paper presented evaluation standard of LOS. In conclusion. the aim of this paper is to suggest modeling based on guidelines for evaluating LOS of mixed traffic street in all traffic modes. It is estimated that this will be influencing indicates for improving pedestrian environment, and Planning mixed traffic street in future.