• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.7
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• pp.827-833
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• 2011

In this study, a simulation model to estimate the current-collection performance of a high-speed train was developed by using a commercial finite element analysis software, SAMCEF. A three-dimensional springDdamperDmass model of a pantograph was created, and its reliability was validated by comparing the receptance of the model to that of the actual pantograph. The wave propagation speed of the catenary model was compared with the analytical wave propagation speed of the catenary system presented in the UIC 799 OR standard. The length of the droppers was controlled, and the pre-sag of the contact wire due to gravity was considered. The catenary and the pantograph were connected by using a contact element, and the contact force variation when the pantograph was moved at velocities of 300 km/h and 370 km/h was obtained. The average, standard deviation, maximum, and minimum values of the contact force were analyzed, and the effectiveness of the developed simulation model was examined.

• Journal of the Korea Convergence Society
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• v.10 no.3
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• pp.73-79
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• 2019

This study simulated external ear canal modeling with different external ear canal lengths, vertical flexion angles, and inner/outer diameter ratios using digital imaging and communications in medicine(DICOM) of the head temporal region and measured the acoustic sensitivity. The experiment was performed by increasing the audible frequency for humans by 200 Hz and expressing the frequency constantly transmitted at 1 Pa as the eardrum acoustic volume and presented the measurements by linear and quadratic curve regression analysis. The results showed that the longer the external ear canal length and the higher the ratio of the outer/inner diameter, the faster the acoustic response at lower frequencies. The acoustic sensitivity correlation of the meta-model using regression analysis showed a 77% influence by the external ear canal length and 5% by the external/internal diameter ratio, while the vertical flexion angle did not show a significant relationship. This showed that auditory acoustic sensitivity of humans is a factor that reacts faster at a low frequency when the external ear canal length is longer and when the difference between the outer and inner diameter is higher.

• The Korean Journal of Archival Studies
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• no.73
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• pp.5-46
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• 2022

This study aims to develop the trustworthiness model for public digital records, as an admissibility framework for establishing trust. The trustworthiness model is deemed to used to identify the qualities of the digital records in their lifecycle, including the identity that could be identified at the time of the creation, integrity obtained from the chain-of-custodial management, the evidence of relationship between business activities and records, and the technical or cognitive accessibility. Based on the analysis of the QADEP model, it was decided to develop a model that could measure the trustworthiness of public digital records in the external measurement type, which are authenticity, reliability, and usability. In line with this direction, the model expanded measurement areas and indicators of the QADEP model through the analysis of ISO 16175-1:2020, and measuring metrics was also proposed so that it could be a measuring instrument for public digital records in Korea, after analysing NAK 19-3. It would be useful to expand the model and to test the approach of the trustworthiness model for public digital records.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5D
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• pp.877-884
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• 2006

GPS is an essential tool for applications that be required high positioning precision, for the velocity field estimation of tectonic plates. The three years data of eight GPS permanent station were analyzed to estimate crustal deformation velocities using Gipsy-oasis II software. The velocity vectors of GPS stations are estimated by linear regression method in daily solution time series. The velocities have a standard deviation of less than 0.1mm/yr and the magnitude of velocities given by the Korean GPS permanent stations were very small, ranging from 25.1 to 31.1 mm/yr. The comparison between the final solution and other sources, such as IGS velocity result calculated from SOPAC was accomplished and the results generally show good agreement for magnitude and direction in crustal motion. To evaluate the accuracy of our results, the velocities obtained from six plate motion model was compared with the final solution based on GPS observation.

• Journal of Navigation and Port Research
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• v.32 no.1
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• pp.37-45
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• 2008

The research on an E-Navigation(E-Nav) strategy development has recently carried out by the IMO sub-committee on safety of navigation(NAV). The design of communication system architecture is a key factor in the E-Nav strategy development and it may drive the direction of a national R&D project on future navigational and marine communication systems. This study aims at designing a standard model of E-Nav communication network architecture, which enhances navigational safety and provides additional benefits in marine transportation. To achieve this purpose, authors have suggested E-Nav services, which are divided into five categories, i.e., safety and security, maritime meteorology, distress, business, and infotainment, by analyzing the related user requirements. As results, this paper proposes the E-Nav communication network architecture that consists of the navigation and communication equipments.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.5
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• pp.129-139
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• 2012

Recent changes in landscape architectural field, such as keen attention on central and local government, checks of other related fields, circumstances both inside and outside the construction industry, assume hostile attitude towards qualification system in landscape architecture. By securing the original function of qualification meets the environmental changes and accords to the technical development, practicality and serviceability of qualification as well as credit rating and professional status can be enforced. Framework redesign on landscape architecture National Technical Qualifications(NTQ) is required in order to meet the demand in the industrial fields and to reflect the technical changes. National Competency Standards(NCS) was selected as a precedent study to enhance the practicality and serviceability of NTQ as well as to avoid duplication on qualified requirements. It would provide a model to redesign the framework of landscape architecture NTQ. In this study, questions in NCS and in landscape architecture certification are compared and analyzed to review the suitability of the present landscape architecture certification items. In conclusion, the creation of master landscape architect under the present system, and the subdivision of the technician's license level to planting technician and the facility are recommended. The ability units to be qualified for each level, which would be used for future NTQ standards and university curriculums in relevant fields, are also suggested in this study.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10A
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• pp.1529-1539
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• 2000

The contact procedure of access channel necessary to set up the originating call has a close relation with the performance and capacity of the base station system in CDMA cellular network. This paper investigates the structure and the operation of the backward channel of IS-95 CDMA standard and explains the related system parameters. We can derive the throughput of the CDMA access channel depending on the arrivals of the access probes per access channel slot, given the system parameters such as cell radius, the maximum number of retransmission, and the error rates of the access and paging channel. It shows that the performance in throughput is much better in the CDMA IS-95 access channel than in the slotted aloha channel. It also gives the reasonable number of the trafic channels in a cell with the given blocking probability.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.489-492
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• 2005

In this paper, we present a system for robust face detection based on wavelet transform using the standard models of image distortion. In the previous works, it was known to be difficult to treat a distorting of image information such as noises and light of the images obtained by a still camera and a movie camera. we analyze the high frequence information by using wavelet transform. This information is used for testing the image distortion and constructing the standard models of image distortion. The experimental results show that our extracting method based on standard models of image distortion is very effective.

• Journal of Internet Computing and Services
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• v.10 no.4
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• pp.115-126
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• 2009

A software size estimation has to be analyzed in the beginning of the software life-cycle and helpful to the prediction of its size and cost. The software cost has been calculated by estimating software size from the user's point of view since the function point method based on international standards was introduced for the estimation of software size in 2004. However, the current function point method is not easy to be exploited for unfamiliar user, and has a problem that it cannot estimate the proper size for software such as engineering software, scientific calculations and simulation with complicated internal computational logic. This paper presents an improved model which can simplify the existing function point measurement procedure, and perform the estimation of software size in easy and fast way at the initial stage of project. Moreover, it presents a mathematical weighted value calculation model which can solve the problem of the fixed complexity weighted value and reflect the characteristics of organization as its data is pilled up. Our evaluation shows that the presented model has advantage that it can measure the size more rapidly than the existing FPA methods and has more correlation with LOC.

• Fire Science and Engineering
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• v.32 no.3
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• pp.76-87
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• 2018

This study describes the damage effects modeling for a quantitative prediction about the hazardous distances from pressurized chlorine saturated liquid tank, which has two-phase leakage. The heavy gas, chlorine is an accidental substance that is used as a raw material and intermediate in chemical plants. Based on the evaluation method for damage prediction and accident effects assessment models, the operating conditions were set as the standard conditions to reveal the optimal variables on an accident due to the leakage of a liquid chlorine storage vessel. A model of the atmospheric diffusion model, ALOHA (V5.4.4) developed by USEPA and NOAA, which is used for a risk assessment of Off-site Risk Assessment (ORA), was used. The Yeosu National Industrial Complex is designated as a model site, which manufactures and handles large quantities of chemical substances. Weather-related variables and process variables for each scenario need to be modelled to derive the characteristics of leakage accidents. The estimated levels of concern (LOC) were calculated based on the Gaussian diffusion model. As a result of ALOHA modeling, the hazardous distance due to chlorine diffusion increased with increasing air temperature and the wind speed decreased and the atmospheric stability was stabilized.