• Journal of Korean Society of Transportation
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• v.22 no.2 s.73
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• pp.145-154
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• 2004

The growing demand for customer-responsive, made-to-order manufacturing is stimulating the need for improved dynamic decision-making processes in commercial fleet operations. Moreover, the rapid growth of electronic commerce through the internet is also requiring advanced and precise real-time operation of vehicle fleets. Accompanying these demand side developments/pressures, the growing availability of technologies such as AVL(Automatic Vehicle Location) systems and continuous two-way communication devices is driving developments on the supply side. These technologies enable the dispatcher to identify the current location of trucks and to communicate with drivers in real time affording the carrier fleet dispatcher the opportunity to dynamically respond to changes in demand, driver and vehicle availability, as well as traffic network conditions. This research investigates key aspects of real time dynamic routing and scheduling problems in fleet operation particularly in a truckload pickup-and-delivery problem under various settings, in which information of stochastic demands is revealed on a continuous basis, i.e., as the scheduled routes are executed. The most promising solution strategies for dealing with this real-time problem are analyzed and integrated. Furthermore, this research develops. analyzes, and implements hybrid algorithms for solving them, which combine fast local heuristic approach with an optimization-based approach. In addition, various partitioning algorithms being able to deal with large fleet of vehicles are developed based on 'divided & conquer' technique. Simulation experiments are developed and conducted to evaluate the performance of these algorithms.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7292-7301
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• 2014

With the development of IT Info-Communications technology, the vehicle with a combination of wireless-communication technology has resulted in significant research into the convergence of the component of existing traffic with information, electronics and communication technology. Intelligent Vehicle Communication is a Machine-to-Machine (M2M) concept of the Vehicle-to-Vehicle. The Vehicle-to-Infrastructure communication consists of safety and the ease of transportation. Security technologies must precede the effective Intelligent Vehicle Communication Structure, unlike the existing internet environment, where high-speed vehicle communication is with the security threats of a wireless communication environment and can receive unusual vehicle messages. In this paper, the Vehicle Identification number between the V2I and the secure message communication protocol was proposed using hash functions and a time stamp, and the validity of the vehicle was assessed. The proposed system was the performance evaluation section compared to the conventional technique at a rate VPKI aspect showed an approximate 44% reduction. The safety, including authentication, confidentiality, and privacy threats, were analyzed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.10 s.352
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• pp.8-17
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• 2006

Recently, the high-speed Internet users increase rapidly and broadband networks have been widely deployed. However, the current TCP congestion control algorithm was designed for relatively narrowband network environments, and thus its performance is inefficient for traffic transport in broadband networks. To remedy this problem, the TCP having an enhanced congestion control algorithm is required for broadband networks. In this paper, we propose an improved TCP congestion control that can sufficiently utilize the large available bandwidth in broadband networks. The proposed algorithm predicts the available bandwidth by using ACK information and RTT variation, and prevents large packet losses by adjusting congestion window size appropriately. Also, it can rapidly utilize the large available bandwidth by enhancing the legacy TCP algorithm in congestion avoidance phase. In order to evaluate the performance of the proposed algorithm, we use the ns-2 simulator. The simulation results show that the proposed algorithm improves not only the utilization of the available bandwidth but also RTT fairness and the fairness between contending TCP flows better than the HSTCP in high bandwidth delay product network environment.

• Korean journal of communication and information
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• v.26
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• pp.259-289
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• 2004

In this study, the use of mainstream online news site and alternative online news site were compared in the aspects of users' characteristics, attitude on online news sites, and using pattern. A survey was conducted for 182 mainstream-only users, 46 alternative online news users, and 47 both sites users, Also, their traffic data of online news sites were analyzed during the 16th presidential election. As a result, it was found that both sites users had the highest political interest and the most progressive political position among the user groups. In the aspect of users' attitude, mainstream-only users were most positive to the mainstream online news site and both sires users were most positive and more involved in alternative online news site. But all user groups set higher credibility on alternative online news site than mainstream online news sire. In the comparison of user size, mainstream online news site has larger user size than alternative online site. However, the user royalty, such as time per person, pages per person, and visiting days per person, was lower than that of the latter. These results suggest thar small but differentiated news sires have royal users, and online news users be segmented according to news contents.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.5
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• pp.146-153
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• 2009

Recently, the research relative to NGN(Next Generation Network) is progressing in 3GPP(The 3rd Generation Partnership Progect), IETF(Internet Engineering Task Force), and so on. Although user needs frequently mobility which is various service pattern, In accordance with the development of these various applications, IMS(IP Multimedia Subsystem) and hierarchical networks ie, Femtocell/WiBro/3G etc is constructed for more user demands which provide service in anytime, anywhere. It is necessary to optimum network selection criterion which consider to wireless signal quality add to user service profile and service network traffic balance. NGN also needs a method to perform heterogeneous handover and to constraint Ping-pong phenomenon when using existing terminal-based handover decision. This paper proposes scheme for network selection and heterogeneous handover procedure in hierarchical wireless multi-access network based on SIP-MIH(Session Initiation Protocol-Media Independent Handover) with IMS by using user service profile that the considerations are dealing with not only selection and registration of various access network but also easy of developing the terminal.

• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.5
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• pp.11-22
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• 2004

A few years ago, many people proposed that a plaza be added to Seoul City Hall. The proposal, however, did not materialize because of traffic confusion. The June 2002 World Cup cheering in front of Seoul City Hall has prodded the public to reconsider the plaza. Even though the exercise failed to gain support, many democratic procedures, opening a Web page and design competitions, and so on were attempted while the design and management of Seoul City Hall Plaza was being deliberated. In the future, the need for proper communication and democratic procedures in the process of making decisions regarding public spaces is expected to increase because of the strengthening of the requirement of participatory and deliberative democracy. An examination of the nature and extent of the communication that has been carried out in relation to the plan to add a plaza to Seoul City Hall will be very helpful in gathering feedback to guide decision-making in regards to the use of other public spaces. Thus, this study has a three-fold purpose. : (1) to examine the theories that may justify the need for public input in relation to decisions made regarding the use of public spaces, and to propose the criteria to be used for the methods of communication (2) to examine the contents and conflicts of communication in relation to the decision made regarding the design and management of Seoul City Hall Plaza and (3) to examine the potential distortion of that communication by analyzing the communication according to the criteria previously proposed. The study method that is used herein is the analysis of articles about the subject matter, which have been posted on the Seoul City Hall Plaza Website and which have been published in newspapers such as the Chosun ilbo, Donga ilbo, the Jungang ilbo, and the Hankyoreh. Diverse article contents are also discussed. As result, there are many differences in the contents and viewpoints of the newspapers that are included in this study. In addition, the related Internet bulletin board has not been used actively, but has contributed to forming public opinion on this issue. Finally, the public demanded to be given acceptable reasons for the results of the design competition, and for the decision to make the grass plaza, which ignores the chosen design in the newspapers or on the Web page. However, their demand was rejected. The communication therefore became distorted and consequently did not become successful in bringing about its intended result.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.1
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• pp.33-41
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• 2012

BIS is an arrival guidance system which is able to supply passengers with bus service condition via Kiosks at a bus stop, internet and mobile service through pinpointing bus location in real time. It is very significant to improve the quality of traffic information by quality control of GIS-based bus network so as to maintain navigational information and to implement reliable BIS. Therefore this study aims to build criteria to quantitatively evaluate data quality of the product in accordance with the process in bus network data and to suggest guideline of quality control. To achieve this, we have categorized geometric and logical errors occurring during constructing bus network database by giving a specific case study on TAGO and set up sectional guideline and procedures to examine database for systematic and coherent quality control management. Proceeding from what has been said above, the outcome of our research leads to quality guarantee for objective and reliable bus network database and is fully expected to bring benefit of providing a more accurate public transportation information and improving reliability of BIS through preventing a variety of errors in system operation in advance.

• The KIPS Transactions:PartA
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• v.15A no.1
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• pp.53-60
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• 2008

Streaming media has contributed to a significant amount of today's Internet Traffic. Like traditional web objects, rich media objects can benefit from proxy caching, but caching streaming media is more of challenging than caching simple web objects, because the streaming media have features such as huge size and high bandwidth. And to support various bandwidth requirements for the heterogeneous ubiquitous devices, a transcoding proxy is usually necessary to provide not only adapting multimedia streams to the client by transcoding, but also caching them for later use. The traditional proxy considers only a single version of the objects, whether they are to be cached or not. However the transcoding proxy has to evaluate the aggregate effect from caching multiple versions of the same object to determine an optimal set of cache objects. And recent researches about multimedia caching frequently store initial parts of videos on the proxy to reduce playback latency and archive better performance. Also lots of researches manage the contents with segments for efficient storage management. In this paper, we define the 9-events of transcoding proxy using 4-atomic events. According to these events, the transcoding proxy can define the next actions. Then, we also propose the segment-based caching policy for the transcoding proxy system. The performance results show that the proposing policy have a low delayed start time, high byte-hit ratio and less transcoding data.

• Science of Emotion and Sensibility
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• v.9 no.2
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• pp.93-100
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• 2006

This paper aims at the development and clinical evaluation of the wireless gyro-mouse system. The wireless gyro-mouse system is a computer interface with gyro-sensor and wireless communication, for the patients with upper-extremity disabled from the traffic accident or stroke to use the computer software i.e. internet browser. In the development, we focused on, firstly, to make the system wireless for the patients to manipulate the mouse easily even on the bed or wheelchair, secondly, to insert the gyro-sensor into a headband for easy don-and-doff and aesthetic appearance, thirdly, to devise a click switch in case of $C5{\sim}C6$ patients and a head nodding detection in case of C4 patients for sending click message to computer operating system. We performed evaluation experiment for patients with upper-extremities disabled from spinal cord injury. The results show that the displacement error of the cursor position against the target position during linear (vertical/horizontal) movement manipulation decreased with trial number. The click rate per minute also increased with trial number. This indicates the developed wireless gyro-mouse system would be more useful to the patients with repetitive use.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.4
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• pp.42-50
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• 2008

The real-time bio-signal monitoring system based on the ZigBee and SIP/RTP has proposed and implemented for telemedicine but that has some problems at the stabilities to transmit bio-signal from the sensors to the other sides. In this paper, we designed and implemented a real-time bio-signal monitoring system that is focused on the reliability and efficiency for transmitting bio-signal at real-time. We designed the system to have enhanced architecture and performance in the ubiquitous sensor network, SIP/RTP real-time transmission and management of the database. The Bluetooth network is combined with ZigBee network to distribute traffic of the ECG and the other bio-signal. The modified and multiplied RTP session is used to ensure real-time transmission of ECG, other bio-signals and speech information on the internet. The modified ECG compression method based on DWLT and MSVQ is used to reduce data rate for storing ECG to the database. Finally we implemented a system that has improved performance for transmitting bio-signal from the sensors to the monitoring console and database. This implemented system makes possible to make various applications to serve U-health care services.