• Journal of Welding and Joining
• /
• v.11 no.3
• /
• pp.34-47
• /
• 1993

Finite element models were developed for thermal and residual stress analysis for the specific welding problems. They were used to evaluate the effectiveness of the various welding heat input models, such as ramp heat input function and lumped pass models. Through the parametric studies, thermal-mechanical modeling sensitivity to the ramp function and lumping techniques was determined by comparing the predicted results with experimental data. The kinetics for residual stress formation during welding can be developed by iteration of various proposed mechanisms in the parametric study. A ramp heat input function was developed to gradually apply the heat flux with variable amplitude to the model. This model was used to avoid numerical convergence problems due to an instantaneous increase in temperature near the fusion zone. Additionally, it enables the model to include the effect of a moving arc in a two-dimensional plane. The ramp function takes into account the variation in the out of plane energy flow in a 2-D model as the arc approaches, travels across, and departs from each plane under investigation. A lumped pass model was developed to reduce the computation cost in the analysis of multipass welds. Several weld passes were assumed as one lumped pass in this model. Recommendations were provided about ramp lumping techniques and the optimum number of weld passes that can be combined into a single thermal input.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.9 no.4
• /
• pp.90-101
• /
• 2010

The existing HiPassPlusCard system is composed of the HiPassPlusCard, a Purchase SAM, a Purchase terminal, a settlement system and OBU. However, this system is confronted by the problem with its incompatibility. This problem occurred because the technology companies made cards in their own ways in respect of the parts which were not yet set by KS standard. Thus if existing HiPassPlusCard user wants to use any other public transportations, user would have to buy other cards and have to bring all them. Also if the HiPlusCard wants to extend their business to apply its technology into infrastructure of the other companies, the HiPlusCard has to construct infra independently so that it causes the such problems of duplicated investment. To solve these problems, we have analyzed and upgraded the existing HiPassPlusCard system, and we designed and developed the Nation-wide Interoperable HiPassPlusCard system. Then the conformity test demonstrated that it is efficiency-oriented and technically performs well. Also we, the HiPlusCard, the Korea Financial Telecommunications & Clearings and the KORAIL NETWORKS, run the Test-bed in Gwangju for 6 months. The test-bed indicated that Nation-wide Interoperable HiPassCard system practically works well.

• Korean Journal of Optics and Photonics
• /
• v.14 no.3
• /
• pp.331-337
• /
• 2003

This paper represents 50 ㎓ narrow band pass filters for fiber optical communication fabricated by dual ion beam sputtering method. We have analyzed the characteristics of the TA$_2$ $O_{5}$ and $SiO_2$ single layers in order to optimize the process conditions for the 50 ㎓ narrow band pass filters, and controlled the film thickness uniformity to less than 0.1 nm deviation by dual peak spike filter pre-deposition. We designed and fabricated 50 ㎓ narrow band pass filters that consist of 216 layers including 4 cavities based on quarter wave optical thickness. Class substrates with high thermal expansion coefficients were used to reduce the film stress. Anti-reflection coating at the rear side of the substrate was also needed to reduce the optical thickness errors of the Optical Monitoring System caused by multiple beam interference between the front side and the rear side of substrate. The optical characteristics of this 50 ㎓ narrow band pass filters are insertion loss of 0.40 ㏈, pass band ripple of 0.20 ㏈, and pass bandwidth at -0.5 ㏈ of 0.20 nm. and isolation bandwidth at -25 ㏈ of 0.6 nm, which satisfy specifications of dense WDM system in fiber optical communications.tions.

• Journal of the Korean Society for information Management
• /
• v.36 no.1
• /
• pp.247-267
• /
• 2019

There has been low use of local information services that public libraries provide, and most of those services are limited only through in-house reading or checkout. Motivated by these issues, the study has developed a mobile application (app, hereafter) entitled as LibPass (a combination of Library and Pass) to propose new local information services that reflect the information needs of users. Regarding the design of LibPass, contents of LibPass are composed of the characteristics of local resources so that users can easily search for information about local culture and tour resources through mobile app. That is, it aims to provide efficient information services on local resources by providing information on accommodations, outdoor programs, and specialized libraries, as well as introducing tour resources. Above all, the services are provided with a single card issued by the National Library of Korea and is convenient to use anywhere in the country. It not only secures reliability and currency by utilizing various contents developed by public institutions, but also provides functions to facilitate specialized services for the local information of libraries. Based on the previous research, the present study derives the factors of quality evaluation of mobile tour information services; it constructs objects of LibPass application by analyzing existing applications and develops the prototype based on logical entity relationship model. This model can contribute to the increased use of local information services and, promotes the public's positive perception of the libraries through user-friendly applications.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.1D
• /
• pp.1-10
• /
• 2010

Safety improvement has been a continuous challenge, especially at toll gate of express highway where traffic conflict often occurs due to frequent lane change by drivers of "Hi-pass" lane and regular "TCS" lane. As a part of research on safety at toll gate, this study videotaped traffic conflict data between vehicles using centrally located "Hi-pass" lane and regular "TCS" lane and analyzed accident risk. According to the correlation analysis of vehicle speed, relative vehicle speed, and sudden vehicle deceleration rate due to traffic conflict, when the relative vehicle speed between centrally located "Hi-pass" lane and regular "TCS" lane increases, sudden vehicle deceleration rate also increases. One of the findings is that centrally located "Hi-pass" lane at toll gate shows different location for traffic conflict, and frequency of traffic conflict and the relative vehicle speed was also different based on vehicle lane use. TA (Time to Accident) analysis shows that accident rate is high at toll gate where Hipass lane is installed in center lane, when the occurrence of sudden vehicle deceleration and deceleration time of vehicles rise for vehicles on "Hi-pass" lane. Furthermore, if the expressway entrance/exit point is closely located to toll gate, TA showed a low value. Thus, it is necessary to reduce the relative vehicle speed in order to improve safety. The Study presents reduction of the relevant vehicular speed and prevention of accidents at the centrally installed "Hi-pass" lane as an important strategy for safety improvement at toll gate.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.12 no.1
• /
• pp.98-108
• /
• 2013

The number of Hi-Pass lanes became 793 lanes at 316 expressway tollgates in 2011 due to the increase in the Hi-Pass use. In spite of the increase in the number of Hi-Pass lanes, there have been increased potential risks in tollgates where vehicles using a Hi-Pass lane must weave with other vehicles using a TCS lane. Therefore, there is a need for study on the safety in tollgates. To this end, this study aims at developing a methodology to evaluate the performance measures of diverse location countermeasures of Hi-Pass lanes in an efficient and systematic way. This study measured the mobility, safety and the convenience of installation and operation of Hi-Pass lanes using a microscopic traffic simulation tool, the surrogate safety assessment model and survey. In addition, this study aggregated the above three performance indexes using weight factors estimated using the AHP technique. For the test site, Dongsuwon interchange was selected. After building the microscopic traffic simulation model for the test site, the location countermeasures of Hi-Pass lanes applicable to the test site were compared with each other in terms of the mobility, safety and installing and operating convenience. As a result, there has been no apparent difference in mobility index based on delays. However, the countermeasures where Hi-Pass lanes are located in inside lanes generally showed better safety performance based on the number of conflicts. In addition, countermeasures with neighboring Hi-Pass lanes were favorable in terms of the safety and the convenience of installation and operation. The methodology proposed in this study was found to be useful to support decision makings by providing critical and quantitative information regarding the mobility, safety and the convenience of installation and operation.

• 한국ITS학회:학술대회논문집
• /
• 2004.11a
• /
• pp.85-88
• /
• 2004

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.06a
• /
• pp.513-514
• /
• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.06a
• /
• pp.501-502
• /
• 2009

• Bulletin of the Korean Mathematical Society
• /
• v.54 no.3
• /
• pp.715-729
• /
• 2017

In this paper, we investigate the existence and multiplicity of solutions for systems driven by two non-local integrodifferential operators with homogeneous Dirichlet boundary conditions. The main tools are the Saddle point theorem, Ekeland's variational principle and the Mountain pass theorem.