• Wind and Structures
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• v.19 no.5
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• pp.467-480
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• 2014

The estimation of wind speed values used in codes and standards is an integral part of the wind load evaluation process. In a number of codes and standards, wind speeds outside of tropical cyclone prone regions are estimated using a single probability distribution developed from observed wind speed data, with no distinction made between the types of causal wind hazard (e.g., thunderstorm). Non-tropical cyclone wind hazards (i.e., thunderstorm, non-thunderstorm) have been shown to possess different probability distributions and estimation of non-tropical cyclone wind speeds based on a single probability distribution has been shown to underestimate wind speeds. Current treatment of non-tropical cyclone wind hazards in worldwide codes and standards is touched upon in this work. Meteorological data is available at a considerable number of United States (U.S.) stations that have information on wind speed as well as the type of causal wind hazard. In this paper, probability distributions are fit to distinct storm types (i.e., thunderstorm and non-thunderstorm) and the results of these distributions are compared to fitting a single probability distribution to all data regardless of storm type (i.e., co-mingled). Distributions fitted to data separated by storm type and co-mingled data will also be compared to a derived (i.e., "mixed") probability distribution considering multiple storm types independently. This paper will analyze two extreme value distributions (e.g., Gumbel, generalized Pareto). It is shown that mixed probability distribution, on average, is a more conservative measure for extreme wind speed estimation. Using a mixed distribution is especially conservative in situations where a given wind speed value for either storm type has a similar probability of occurrence, and/or when a less frequent storm type produces the highest overall wind speeds. U.S. areas prone to multiple non-tropical cyclone wind hazards are identified.

• Journal of Korean Society on Water Environment
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• v.34 no.3
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• pp.251-269
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• 2018

In 1997, the environmental score (Q) corresponding the tolerance value of Korean benthic macroinvertebrate species and the related biotic score, the ecological score of benthic macroinvertebrates (ESB) were proposed; ESB was similar to Beck's biotic index or Chandler's biotic score. This study was carried out to revise the Q values of individual species and the assessment scheme of ESB based on the taxonomic performance and ecological information accumulated since then. The original ESB was renamed as TESB (total ESB), and AESB (average ESB) was newly proposed. AESB is calculated by dividing the TESB (for a given station) by the number of species present in the sample. In this study, TESB showed a positively skewed distribution, while AESB showed a negatively skewed distribution. The correlation between TESB and the concentration of $BOD_5$ was a little stronger than that of the original ESB. TESB showed a very strong correlation (correlation coefficient r = 0.98) with Margalef's species richness, of which correlation coefficient was higher than that of AESB (r = 0.85). AESB showed a strong correlation (r = -0.79) with the concentration of $BOD_5$, while TESB showed a weaker correlation (r = -0.67). Applying TESB and AESB together in an assessment of the environment may be comprehensive because the physical and chemical states of the environment can be evaluated together. AESB is less dependent on the sample size, while TESB tends to increase as the sample size increases. In the evaluation of the environment using TESB, it is necessary to standardize the methods on monitoring.

• Journal of Power System Engineering
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• v.21 no.4
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• pp.57-61
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• 2017

The vehicle label fuel economy is used as an energy management indicator nationwide. It induces technology development of automobile manufacturers and plays a role of providing information when purchasing a consumer vehicle. However, consumers who purchase a new vehicle continued to complain that the label fuel economy is different from the mandatory fuel economy rate. The domestic fuel economy measurement method is the same as the North American measurement method. The results of the two test modes (urban (FTP-75 mode), highway (HWFET mode)) are calculated in five test modes reflecting various environmental conditions and driving patterns 5-cycle correction formula is used which is equivalent to the fuel efficiency value. In this study, to solve the consumers' curiosity about the fuel economy of new vehicle, we use domestic fuel economy measurement method to measure the new car condition within 150 km of driving distance and the cumulative driving distance condition of domestic label fuel economy test vehicle. A comparative evaluation of fuel economy was carried out for a durability vehicle of $6,500{\pm}1,000km$. A result, mean value of the fuel economy of the four gasoline vehicles increased by 2.7 % in the city center mode and by 2.5 % in the highway mode in the durable vehicle compared new vehicle. And in the case of the diesel vehicle it increased by 2.5 % and 3.9 % respectively. The harmful exhaust gas emitted from the vehicle also resulted in more emissions of both gasoline and diesel vehicles in new vehicles. It is considered that the increase of the frictional force of the vehicle driving system and the lubricating oil system would have an effect on the reduction of the fuel economy of the new vehicle, and it was found that the fuel economy and the exhaust gas were improved by proper cumulative distance (domesticate) to the new vehicle.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.695-702
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• 2006

In GIS-based Spatial Decision-making Support System (SDSS), the Boolean logic by conventional simple overlay method contains two problems. One is losing lots of information in analysis process, the other is unable to reflect of weighting values between evaluated items. Therefore, evaluation system as Analytic Hierarchy Process (AHP) needs to improve these problems effectively. The purpose of this study is to provide the benefit of AHP method and GIS spatial analysis in site analysis for crop cultivation. First, the weighting value of AHP for topography, distribution grade of water, property of soil and slope items are evaluated throughout survey to experts of soil, crop and agricultural management fields. On the basis of these weighting value of AHP by items, site suitability analysis for black raspberry cultivation is performed. To estimate the benefit of AHP method, the current cultivating map of black raspberry is constructed in Ssangchi-myeon district. In comparison with site analysis of Boolean logic, site analysis of AHP method shows more realistic.

• Journal of Korean Society on Water Environment
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• v.23 no.4
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• pp.467-473
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• 2007

Although the dominant land use at the Imha-dam watershed is forest areas, soil erosion has been increasing because of intensive agricultural activities performed at the fields located along the stream for easy-access to water supply and relatively favorable topography. In addition, steep topography at the Imha-dam watershed is also contributing increased soil erosion and sediment loads. At the Imha-dam watershed, outflow has increased sharply by the typhoons Rusa and Maemi in 2002, 2003 respectively. In this study, the Soil and Water Assessment Tool (SWAT) model was evaluated for simulation of flow and sediment behaviors with long-term temporal and spatial conditions. The precipitation data from eight precipitation observatories, located at Ilwol, Subi and etc., were used. There was no significant difference in monthly rainfall for 8 locations. However, there was slight differences in rainfall amounts and patterns in 2003 and 2004. The topographical map at 1:5000 scale from the National Geographic Information Institute was used to define watershed boundaries, the detailed soil map at 1:25,000 scale from the National Institute of Highland Agriculture and the land cover data from the Korea Institute of Water and Environment were used to simulate the hydrologic response and soil erosion and sediment behaviors. To evaluate hydrologic component of the SWAT model, calibration was performed for the period from Jan. 2002 to Dec. 2003, and validation for Jan. 2004 to Apr. 2005. The $R^2$ value and El value were 0.93 and 0.90 respectively for calibration period, and the $R^2$ value and El value for validation were 0.73 and 0.68 respectively. The $R^2$ value and El value of sediment yield data with the calibrated parameters was 0.89 and 0.84 respectively. The comparisons with the measured data showed that the SWAT model is applicable to simulate hydrology and sediment behaviors at Imha dam watershed. With proper representation of the Best Management Practices (BM Ps) in the SWAT model, the SWAT can be used for pre-evaluation of the cost-effective and sustainable soil erosion BMPs to solve sediment issues at the Imha-dam watershed. In Korea, the Universal Soil Loss Equation (USLE) has been used to estimate the soil loss for over 30 years. However, there are limitations in the field scale mdel, USLE when applied for watershed. Also, the soil loss changes temporarily and spatially, for example, the Imha-dam watershed. Thus, the SW AT model, capable of simulating hydrologic and soil erosion/sediment behaviors temporarily and spatially at watershed scale, should be used to solve the muddy water issues at the Imha-dam watershed to establish more effective muddy water reduction countermeasure.

• Culinary science and hospitality research
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• v.6 no.3
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• pp.25-55
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• 2000

AS the number of tourist has been increased. hotel industry will be able to not be existed and developed if not adapted to the need of customer's which is changed according to the change of Hotel's function. Traditionally. F&B department is enlarged compared to the past. But. it cause negative result in terms of clear profit. A menu is a marketing tool which delivers restaurant's image aid message to customers and communicate need and wants to restaurant. So far, studies on menu have been done in an analytical way from a management's viewpoint and inadequate to reflect customer's need and wants. A research on customer's menu selection procedure is critical to satisfying their needs and wants yield profit. This study examined the theories on menu-design and customer behavior through literature review and verified hypotheses through an empirical analysis. A questionnaire-survey had been used in luxury hotel's main grills and all most restaurants in Seoul. Collected data were analyzed. using SPSS/PC+ package. The important findings are as follows. In this study is to examine the factors that have an influence on customer's menu selection. The factors affected the customers' menu selection of hotel restaurant in the four factors. Four factors are hotel's restaurant of environmental factor. menu-choice factor. value of menu items, information. Correction between the evaluation criteria and selection of menu was examined. All four evaluation criteria, menu-choice factor was found to be most strongly collected with selection of menu. In conclusion, As a study on the Customer' menu Selection Behavior factor of Restaurant Menus in Hotels, It raises to exert us in the menu management of hotel restaurant.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.09a
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• pp.93-116
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• 2005

SPT-Uphole tomography method was introducedand verified in this paper. In SPT-Uphole method, SPT (Standard Penetration Test) which is common in site investigation, was used as a source and several surface geophones in line were used as receivers. Shear wave velocity (Vs) distribution map which has triangular shape around the boring point can be obtained by tomography inversion. The factors for obtaining reliable result of SPT-Uphole tomography are exact travel time information and accurate inversion method. To establish of the SPT-Uphole tomography procedure, the most reliable method for obtaining exact travel time information and verification of tomography inversion method were studied by using theoretical travel time information and finite element method (FEM) analysis. finally, SPT-Uphole tomography method was performed at the weathered soil site in Kimje. By comparing with several boring data including SPT-N value, feasibility of this method was verified in the field.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.6
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• pp.117-131
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• 2010

This study was conducted to utilize as basic information for the construction of conservation and estimation system for Palustrine wetland, which was badly managed and imprudently reclaimed, through the analysis of distribution characteristics and the estimation of conservation value for sample sites (eight wetlands) in rural area. As the result of wetland type classification, these wetlands was classified by 4 types (Permanent freshwater marshes/pools, ponds, Aquaculture ponds, and Seasonally flooded agricultural land) by Ramsar system, 3 types (Emergent Wetland, Aquatic Bed, and Scrub-Shrub Wetland) by NWI (Cowardin) System, 5 types (Farm Pond Depression, Under-flow wetland, Man-made Pond Depression, Abandoned Paddy Fields Wetland, and Reservoir Shore) by National Wetland's Categorical System, and 3 types (Aquatic Bed Wetland, Emergent Wetland, and Forested Wetland) by Lee (2000) System. These results suggest us developing the new type classification system for small Palustrine wetland in Korean rural areas. The score of function assessment (The Modified RAM) for small Palustrine wetlands was high at the wetlands nearby hills and rice paddy fields, and low at those nearby upper fields, which was mainly affected by land-use and vegetation. The functions as 'Flood/Storm Water Storage', 'Runoff Attenuation', 'Water Quality Protection' were resulted by the structural difference of inflow and outlet. Some functions as 'Wetland size', 'Wetland to immediate watershed ratio', 'Presence of boat traffic', 'Maximum water depth', 'Fetch of water's body' of RAM were not appropriate in evaluation of small wetlands in rural area. Which suggest us developing the new function assessment system for small Palustirne wetland in Korean rural areas.

• Structural Monitoring and Maintenance
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• v.5 no.4
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• pp.463-488
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• 2018

In the last decades, research efforts have been spent to investigate the effect of prestressing on the dynamic behaviour of prestressed concrete (PSC) beams. Whereas no agreement has been reached among the achievements obtained by different Researchers and among the theoretical and the experimental results for simply supported beams, very few researches have addressed this problem in continuous PSC beams. This topic is, indeed, worthy of consideration bearing in mind that many relevant bridges and viaducts in the road and railway networks have been designed and constructed with this structural scheme. In this paper the attention is, thus, focused on the dynamic features of continuous PSC bridges taking into account the effect of prestressing. This latter, in fact, contributes to the modification of the distribution of the bending stress along the beam, also by means of the secondary moments, and influences the flexural stiffness of the beam itself. The dynamic properties of a continuous, two spans bridge connected by a nonlinear spring have been extracted by solving an eigenvalue problem in different linearized configurations corresponding to different values of the prestress force. The stiffness of the nonlinear spring has been calculated considering the mechanical behaviour of the PSC beam in the uncracked and in the cracked stage. The application of the proposed methodology to several case studies indicates that the shift from the uncracked to the cracked stage due to an excessive prestress loss is clearly detectable looking at the variation of the dynamic properties of the beam. In service conditions, this shift happens for low values of the prestress losses (up to 20%) for structure with a high value of the ratio between the permanent load and the total load, as happens for instance in long span, continuous box bridges. In such conditions, the detection of the dynamic properties can provide meaningful information regarding the structural state of the PSC beam.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.227-239
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• 2006

Reliability prediction provides a rational basis for design decisions such as the choice between alternative concepts, choice of part quality levels, derating factors to be applied, use of proven versus state-of-the-art techniques, and other factors. For this reasons, reliability prediction is essential functions in developing space systems. The worth of the quantitative expression lies in the information conveyed with the numerical value and the use which is made of that information and reliability prediction should be initiated early in the configuration definition stage to aid in the evaluation of the design and to provide a basis for item reliability allocation (apportionment) and establishing corrective action priorities. Reliability models and predictions are updated when there is a significant change in the item design availability of design details, environmental requirements, stress data, failure rate data, or service use profile. In this paper, the procedure, selection of reliability data and methods for space system reliability prediction is presented.