• Journal of Korean Society of Transportation
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• v.28 no.6
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• pp.85-97
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• 2010

The present study aims at estimating the model of bus bunching duration along with its influential determinants in an attempt to understand the status of bus bunching being created by buses from various routes converging into one bus stop. To do so, the duration analysis, a well-known survival analysis, was adopted in order to capture the distribution of duration time as for 8 base lines, accordingly developing the model best fit for weibull distribution. Key attention to draw out the duration time model for bus bunching phenomena was laid, by analyzing 18 impact factors, on such criterion variables as number of berth, number of bus line in each berth and maximum capacity of on-and-off passengers in each line. Comparison in two typical types of bus lane was made between bus-only center lane(Dobong Mia-ro) and normal street-side lane(Tongil Euiju-ro). In this regard, the study, based on the model as above, suggested appropriate alternatives to improve the bus operation by effectively controlling bus bunching.

• Korean Journal of Veterinary Research
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• v.44 no.4
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• pp.607-613
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• 2004

Helicobacter pylori (H. pylori)-infection is an important pathogen of stomach cancer after chronic gastritis and ulceration in the stomach and duodenum. However, the virulences of H. pylori strains have not been well-defined between clinical isolates. This study was designed to establish water-immersion-restraint stress (WIRS) model in mongolian gerbil for comparison of pathogenicity of H. pylori strains. To determine an optimal duration time for WIRS model in gerbil, 5-week-old Mongolian gerbils were divided into different groups by WIRS duration time. After graded duration of WIRS, the macroscopic ulcer index (UI) was measured with the stomach and duodenum of sacrificed animal. There were no significant differences between male and female in same duration group. However, the UI increased significantly in a time-dependent fashion. The group of 6 hours-WIRS animals showed severe hemorrhage and ulceration in their stomach and duodenum. On the other hand, the very mild lesions induced in 2 hours-treated animals. Therefore, we determined an optimal duration time for WIRS model in gerbil as 4 hours. Thereafter, we evaluated whether this WIRS model in gerbil could be used as an useful tool for in vivo comparison of pathogenicity of H. pylori strains by enhancement of pathological severity in H. pylori-infected gerbils. Mongolian gerbils were divided into H. pyloriinfected and PBS-inoculated groups. Thereafter, they were divided again into 4 hours-WIRS and no WIRS subgroups. After treatment, the severity of pathological changes was evaluated in a same manner with previous duration-determining experiment. When the animals were exposed to WIRS, the UI was significantly higher in the infected group than in the uninfected group. These results suggested that the established gerbil-WIRS model in this study enhanced effectively the severity of pathogenic changes in the H. pylori-infected Mongolian gerbils and could be used as an useful tool for in vivo comparison of pathogenicity of H. pylori strains.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.1
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• pp.39-51
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• 1999

This study has an object to evaluate runoff characteristics with ILLUDAS model and SWMM owing to each rainfall distribution type of Huff's quartile and each rainfall duration time of 30 ,60, 120 and 180 minutes. As a result of this study, Type-Ⅰ Extreme (TIE) rainfall distribution pattern with Huff's 2nd quartile is adequate for Cheju volcanic island . To decide optimal rain fall duration , time of concentration and critical duration should be compared and analyzed each other. In this study, 30 and 120 miniutes were suggeste to iptiaml duration time of A and B study basins. It is concluded that the magnitude of peak runoff discharge is maximum with Huff's 4th quartile, and that of total runoff volume is maximum with Huff's 4th quartile for ILLUDAS model and with Huff's 1st quartile for SWMM. As rainfall duration time increasing is increasing . Also in case of total runoff volume, volumen by SWMM is less than by ILLUDAS model as to variation ratio of total runoff volume in A and B study basin. Therefore, the resulots of this study canb e sued as basic data in determining adequate rainfoal duration time and rainfall distribution type and used for urban drainage systems analysis and design at small urbanization catchment is Cheju volcanic island.

• Structural Engineering and Mechanics
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• v.9 no.1
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• pp.69-88
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• 2000

A relatively simple model of a buried structure response to a surface loading that can simulate a possible opening and closure of a gap between the soil and the structure is presented. Analysis of the response of small and medium scale buried roof slabs under surface impulsive loading shows that the model's predictions are in fairly good agreement with the experimental results. Application of the model to a study case shows the relative influence of system parameters such as, the depth of burial, the arching coefficient, and the roof thickness, on the interface pressure and on the roof displacement. This model demonstrates the effect of a gap between the structure and the soil. The relative importance of including a gap opening and closure in the analysis is examined by the application of the model to a study case. This study results show that the deeper the depth of burial, the longer the gap duration, and the shorter the duration of the initial interface impact, while the higher the soil's shear resistance, the higher the gap duration, and the shorter the initial interface impact duration.

• Journal of the Korea Computer Industry Society
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• v.7 no.3
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• pp.191-198
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• 2006

Area of software measurement is active more than thirty years. There is a huge collection of researches but still no concrete software development effort, duration and cost estimation model. The data sets used to conduct previous studies in the duration estimation model are often small and not too recent, these types of models should not be apply in recent projects that have complex architecture and various development environment. Therefore, Oligny et al. presents empirical models that predict software project duration in accordance with project platform based on project effort using the log data transformation. These models are based on the analysis of 396 project data provided by release 4 of the ISBSG Benchmark. Applying Oligny et al.'s models to 534 project data provided release 6 of the ISBSG Benchmark, the project duration is affected by development type more than development platform. Therefore, This paper presents the model of duration estimation according to development type. This paper proves the duration is more affected by development type than development platform. And, The model according to development type is more adequate for duration estimation.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.3
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• pp.116-131
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• 2014

In this study, sunshine environment in an urban area is analyzed using a numerical model which considers sunshine-duration blocking by topography and buildings. The numerical model used in this study has an improvement in the algorithm detecting sunshine duration in the model domain. The main improvement in the algorithm is to detect sunshine duration using all the surfaces of any grid cell(the previous model uses the center of any grid cell). The improvement in the algorithm gives more accurate evaluation of sunshine duration at corner surfaces of buildings. Using the improvement model and geographic information system(GIS) data, sunshine environment is analysed at an building-congested area in Busan for a week in four seasons. The results show that sunshine duration can be much changed by apartment complexes, high-rise buildings, topography in the model domain.

• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.135-148
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• 2007

Understanding the relation between characteristics of an accident and its duration is crucial for the efficient response of accidents and the reduction of total delay caused by accidents. Thus the objective of this study is to model accident duration using an AFT metric model. Although the log-logistic and log-normal AFT models were selected based on the previous studies and statistical theory, the log-logistic model was better fitted. Since the AFT model is commonly used for the purpose of prediction, the estimated model can be also used for the prediction of duration on freeways as soon as the base accident information is reported. Therefore, the predicted information will be directly useful to make some decisions regarding the resources needed to clear accident and dispatch crews as well as will lead to less traffic congestion and much saving the injured.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.902-907
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• 2005

This study was undertaken to develop a comprehensive scheduling method which applied the core concept(DBR) of TOC to PERT, and to combine Monte Carlo Simulation to revise the uncertainties of activities then to eliminate project duration uncertainty. Most of the project duration overlooks the fact that in spite of minimizing the project duration, the uncertainty of constrained resources still puts the reliability of project duration in jeopardy. For the contractor, however, the most important thing is to comply the project scheduling with the planning to reduce the uncertainty of the project activities, operational interaction and project duration. In order to demonstrate that the model can be used in construction project, the scheduling of a steel-structure project was used as a case study to verify the validity of this model.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.892-896
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• 2005

This paper collected 132 schools reconstruction projects in central Taiwan, which received the most serious damage from the Chi-Chi Earthquake. Regression analysis was implemented to build the prediction model of the cost and the duration for the collected projects. It is found that the cubic regression models are capable for predicting the cost and the duration of the projects contracted by the central agency of which the contracting awarding approach was based on the most advantageous tendering (MAT) approach. On the other hand, power regression models are capable for predicting the cost and the duration of the projects contracted through the low bid tendering (LBT) approach. It is also found that the performance of the regression prediction model differs in accordance with organizations that contracted the reconstruction projects.

• Earthquakes and Structures
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• v.3 no.1
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• pp.1-15
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• 2012

An empirical predictive relationship correlating bracketed duration to earthquake magnitude, site-to-source distance, and local site conditions (i.e. rock vs. stiff soil) for stable continental regions of North America is presented herein. The correlation was developed from data from 620 horizontal motions for central and eastern North America (CENA), consisting of 28 recorded motions and 592 scaled motions. The bracketed duration data was comprised of nonzero and zero durations. The non-linear mixed-effects regression technique was used to fit a predictive model to the nonzero duration data. To account for the zero duration data, logistic regression was conducted to model the probability of zero duration occurrences. Then, the probability models were applied as weighting functions to the NLME regression results. Comparing the bracketed durations for CENA motions with those from active shallow crustal regions (e.g. western North America: WNA), the motions in CENA have longer bracketed durations than those in the WNA. Especially for larger magnitudes at far distances, the bracketed durations in CENA tend to be significantly longer than those in WNA.