• The Journal of Korean Institute of Communications and Information Sciences
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• 제40권1호
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• pp.96-107
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• 2015

VANET technologies provide real-time traffic information for mitigating traffic jam and preventing traffic accidents, as well as in-vehicle infotainment service through Telematics/Intelligent Transportation System (ITS). Due to the rapid increasement of various requirements, the vehicle communication with a limited resource and the fixed frame architecture of the conventional techniques is limited to provide an efficient communication service. Therefore, a new flexible operation depending on the surrounding situation information is required that needs an adaptive design of the network architecture and protocol for efficiently predicting, distributing and sharing the context-aware information. In this paper, Vehicle-to-Infrastructure (V2I) based on communication between vehicle and a Road Side Units (RSU) and Vehicle-to-Vehicle (V2V) based on communication between vehicles are effectively combined in a new MAC architecture and V2I and V2V vehicles collaborate in management. As a result, many vehicles and RSU can use more efficiently the resource and send data rapidly. The simulation results show that the proposed method can achieve high resource utilization in accordance. Also we can find out the optimal transmission relay time and 2nd relay vehicle selection probability value to spread out V2V/V2I collaborative schedule message rapidly.

• Applied Microscopy
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• 제36권1호
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• pp.7-16
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• 2006

A new remote access system for a 1.3 MV high voltage electron microscope has been developed. Almost all essential functions for HVEM operation, huck as stage control, specimen tilting, TV camera selection and image recording, are successfully embedded into this prototype of the remote system. Particularly, this system permits perfect and precise operation of the goniometer and also controls the high resolution digital camera via simple Web browsers. Transmission of control signals and communication with the microscope is accomplished via the global ring network for advanced applications development (GLORIAD). This fact makes it possible to realize virtual laboratory to carry out practical national and international HVEM collaboration by using the present system

• Archives of design research
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• 제19권2호
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• pp.91-98
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• 2006

The product convergence and complex application environment raise the need of multi-modal interface which enables us to interact products through various human senses. The sense of vision has been used predominantly more than any other senses for the traditional and general information gathering situation, but in the future which will be developed based on the digital network technology, the practical use of the various senses will be desired for more convenient and rational usage of the information appliances. The sense of auditory which possibility of practical use is becoming higher than ever with the sense of vision, the possible usage will be developed broader and in the various ways in the future. Based on this situation, the characteristics of the written language and the colloquial language and the comparative analysis of the difference between male and female's reaction for each language were examined through this study. To achieve this purpose, the literature research about the diverse components of the language system was peformed. Then, some peculiar characters of the sense of vision and auditory were reviewed and the appropriate experimentation was planned and carried out. The result of the accomplished experimentation was examined by the objective analysis method. The main results of this study are as follows: first, the reaction time for written language is shorter than colloquial language, second, there is a partial difference between the male's and female's reaction for those two stimuli, third, there is no selection bias between the sense of sight and the sense of hearing. I think the continuous development of the broad and diverse ways of study for various senses is needed based on this study.

• Journal of KIISE:Computer Systems and Theory
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• 제31권8호
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• pp.432-444
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• 2004

In this paper, we construct the TMO-based object group model on distributed environment, and analyze and evaluate the executability for distributed real-time service of our object group model by developing the distributed real-time application simulator applying the model. The Time-triggered Message-triggered Object(TMO) is a real-time server object having real-time property itself. The TMO-based object group is defined as a set of objects which logically reconfigured the physically distributed one or more TMOs on network by a given distributed application. For supporting group management of the server objects, the TMO-based object group we suggested provides the functions which register and withdraw the solver objects as a group member to an arbitrary object group, and also provides the functions which insert and delete the access rights of server objects from clients. Also, our model was designed and implemented to support the appropriate object selection and dynamic binding service for a single TMO as well as the duplicated TMOs, and to support the real-time scheduling service for the clients which are requesting the service. Finally, we developed the Defence System against Invading Enemy Planes(DSIEP) simulator as a practical example of distributed real-time application by applying our model, and evaluated the adaptability of distributed service strategies for the group components and the executability of real-time services that the TMO-based object group model provides.

• Journal of KIISE:Information Networking
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• 제30권3호
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• pp.407-415
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• 2003

As services requesting data transfer from a sender to a multiple number of receivers become popular, efficient group communication mechanisms like multicast get much attention. Since multicast is more efficient than unicast in terms of bandwidth usage and group management for group communication, many multicast protocols providing scalability and reliability have been proposed. Recently, router-supported reliable multicast protocols have been proposed because routers have the knowledge of the physical multicast tree structure and, in this scheme, repliers which retransmit lost packets are selected by routers. Repliers are selected dynamically based on the network situation, therefore, any receiver within a multicast group can become a replier Hence, all receivers within a group maintains a buffer for loss recovery within which received packets are stored. It is an overhead for all group receivers to store unnecessary packets. Therefore, in this paper, we propose a new scheme which reduces resource usage by discarding packets unnecessary for loss recovery from the receiver buffer. Our scheme performs the replier selection and the loss recovery of lost packets based on the LSM [1] model, and discards unnecessary packets determined by ACKs from erasers which represent local groups.

• Tunnel and Underground Space
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• 제15권2호
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• pp.119-128
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• 2005

Although the evaluation of the mechanical properties and behavior of jointed rock masses is very important for the design of tunnel and underground openings, it has always been considered the most difficult problem. One of the difficulties in describing the rock mass behavior is the selection of the appropriate constitutive model. This limitation may be overcome with the progress in discrete element software such as PFC, which does not need the user to prescribe a constitutive model for rock mass. In this paper, a 30\;m\;\times\;30\;m\;\times\;30\;m m jointed rock mass of road tunnel site was analyzed. h discrete fracture network was developed from the joint geometry obtained from core logging and surface survey. Using the discontinuities geometry from the DFN model, PFC simulations were carried out, starting with the intact rock and systematically adding the joints and the stress-strain response was recorded for each case. With the stress-strain response curves, the mechanical properties of jointed rock masses were determined. As expected, the presence of joints had a pronounced effect on mechanical properties of the rock mass. More importantly, getting the mechanical response of the PFC model doesn't require a user specified constitutive model.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제11권1호
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• pp.163-172
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• 2007

The web as global network includes text document, video, sound, etc and connects each distributed information using link Through development of web, it accumulates abundant information and the main is text based documents. Most of user use the web to retrieve information what they want. So, numerous researches have progressed to retrieve the text documents using the many methods, such as probability, statistics, vector similarity, Bayesian, and so on. These researches however, could not consider both the subject and the semantics of documents. As a result user have to find by their hand again. Especially, it is more hard to find the korean document because the researches of korean document classification is insufficient. So, to overcome the previous problems, we propose the korean document classification method for semantic retrieval. This method firstly, extracts TF value and RV value of concepts that is included in document, and maps into U-WIN that is korean vocabulary dictionary to select the topic of document. This method is possible to classify the document semantically and showed the efficiency through experiment.

• Journal of the Korean Society for Railway
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• 제19권4호
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• pp.539-546
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• 2016

It is over 12 years since the launch of Korea Train eXpress (KTX) services. Demand for the KTX has been on the increase continuously but few studies have been produced related to this phenomenon. KTX passenger demand has been constantly increasing due to influencing factors such as the expansion of network, rise of oil prices, etc. In this study, our main focus is to verify that there are other types of elements that are causing an increase in KTX demand; our approach looks at changes in social and psychological aspect that have occurred due to the reduction of travel time and cost, as well as the imposition of a five-day workweek. In other words, we considered diffusion theory in the marketing area, which affects product selection and purchasing attitudes, as a key factor that is causing passenger demand to increase. That is to say that it is hypothesized that the demand for travel on the KTX has increased due to the train's utility, which is spread by the diffusion effect Therefore, the Bass diffusion model was applied to explain the dramatic increase in KTX passenger demand. Based on this foundation, it was also discussed how certain marketing strategies that incorporate the diffusion effect should be considered variously for sustainable management of rail transportation, while considering a steady passenger demand.

• Journal of the Korean Society of Hazard Mitigation
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• 제11권3호
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• pp.229-235
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• 2011

In order to manage a sewer system effectively, flow conditions such as flux, water quality, Infiltration and Inflow (I/I), Combined Sewer Overflows (CSOs), etc need to be monitored on a regular base. Therefore, in sewer networks, a monitoring is so important to prevent the river disaster. Monitoring all nodes of an entire sewer system is not necessary and cost-prohibitive. Water quality monitoring points that can represent a sewer system should be selected in a economical manner. There is no a standard for the selection of monitoring points and the quantitative analysis of the observed data has not been applied in sewer system. In this study, the entropy method was applied for a sewer network to evaluate and determine the optimal water quality monitoring points using genetic algorithm. The entropy method allows to analyze the observed data for the pattern and magnitude of temporal water quality change. Since water quality measurement usually accompanies with flow measurement, a set of installation locations of flowmeters was chosen as decision variables in this study.

• Annals of Surgical Treatment and Research
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• 제95권5호
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• pp.278-285
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• 2018

Purpose: We investigated the clinical outcomes of deceased donor kidney transplantation (KT) using kidneys with terminal acute kidney injury (AKI). Methods: Between February 2000 and December 2013, we performed 202 deceased donor renal transplants from 159 brain dead donors. According to the expanded criteria donor (ECD) and AKI network criteria, we divided 202 recipients into 4 groups: Group I: Non-AKI & standard criteria donor (SCD) (n = 97); group II: Non-AKI & ECD (n = 15); group III: AKI & SCD (n = 52); and group IV: AKI & ECD (n = 38). Results: The incidence of delayed graft function (DFG) was significantly higher in patients with AKI than it was in the non-AKI group (P = 0.008). There were no significant differences among the 4 groups in graft survival (P = 0.074) or patient survival (P = 0.090). However, the long-term allograft survival rate was significantly lower in group IV than it was in other groups (P = 0.024). Conclusion: Allografts from deceased donors with terminal AKI had a higher incidence of DGF than did those from donors without AKI. However, there is no significant difference in graft and patient survival rates among the groups. So, the utilization of renal grafts from ECDs with terminal AKI is a feasible approach to address the critical organ shortage.