• Journal of Technology Innovation
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• v.15 no.2
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• pp.103-122
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• 2007

This paper examines the social development process of technological innovation for national emergency management. There are relatively few studies on how technological innovations are developed and deployed within social context. This paper investigates innovation processes within social contexts and the role of innovation actors such as citizens, government, and private sector. The the Real-time Disaster Management System (RDMS) is an innovation for citizens to transmit digital images and video clips on disaster toward professional organizations to respond to disasters. This case shows how an innovation in disaster management was developed by social interactions, how open innovation mechanism was deployed, and how end-users involved in innovation processes for disaster management. Finally this paper suggests implications to accelerate innovations for social welfare and social change.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.27.2-27.2
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• 2011

The Total Electron Content (TEC) measured from Global Positioning System (GPS) can be continuously or peculiarly increased (positive ionospheric storm) or decreased (negative ionospheric storm) with solar and geomagnetic activities as well as the chemical and dynamic processes with thermosphere in the mid-latitudes. The ionospheric storm is not easy to predict owing to its difficult mechanism, and the real-time GPS TEC monitoring may be useful to follow ionospheric response to solar and geomagnetic storms. Korea Astronomy & Space Science Institute has continuously monitor GPS TEC over Korea Peninsula in near real-time of 10 minutes to watch activities. In this presentation, we will report the variation of GPS TEC over Daejeon and JeJu in Korea during the period of solar flare eruption and geomagnetic storm events in 2011. These events in 2011 will be compared with the event in October 2003 and November 2004.

• Journal of Information Processing Systems
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• v.4 no.2
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• pp.41-52
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• 2008

In this paper, we discuss a novel reservation-based, asynchronous MAC protocol called 'Multi-rate Multi-hop MAC Protocol' (MMMP) for multi-hop ad hoc networks that provides QoS guarantees for multimedia traffic. MMMP achieves this by providing service differentiation for multirate real-time traffic (both constant and variable bit rate traffic) and guaranteeing a bounded end-to-end delay for the same while still catering to the throughput requirements of non real time traffic. In addition, it administers bandwidth preservation via a feature called 'Smart Drop' and implements efficient bandwidth usage through a mechanism called 'Release Bandwidth'. Simulation results on the QualNet simulator indicate that MMMP outperforms IEEE 802.11 on all performance metrics and can efficiently handle a large range of traffic intensity. It also outperforms other similar state-of-the-art MAC protocols.

• Journal of Korea Multimedia Society
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• v.8 no.6
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• pp.798-806
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• 2005

In this paper, we suggest a game system that can support network modules for multi-platform based video games, and built a system that can convert from a single-user game to multi-user game. In this system, we bring in an initial delay buffering scheme on clients to handle any periods of latency occurring from the load fluctuation in a network, when a real-time game is played, and shows that stable play for a game is achieved as the result of the scheme. This paper also presents a retransmission algorithm based on the history of game commands to handle drawbacks of UDP mechanism. And, we evaluate the network delay and packet loss using the simulation tool NS2, and shows the case of 0.3 second buffer delay is the most suitable for recovery.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.11
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• pp.2521-2530
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• 1997

In this paepr, we present a video-on-demand (VOD) system design model that address and integrates a number of inter-related issues. Then with analysis and performance evaluation, we investigate various aspects of disk and buffer managements in the given model. Based on the analysis results, we suggest that a distributed buffering scheme with intermediate buffers may te useful to transform bursty disk accesses into a continuous stream for for glitch-free performance of VOD systems. Also, through simulation, we illustrate that massive multimedia information storage design techniques such as prefetching, clustered striping, and real-time disk scheduling integrated with the distributed buffering mechanism may enhance end-to-end real-time performance of VOD systems under wide-area networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8B
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• pp.657-666
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• 2008

The intersection collision avoidance service among various telematics application services is regarded as one of the most critical services with regard to safety. In such safety applications, real-time, correct transmission of service is required. In this paper, we study on efficient infrastructure architecture for intersection collision avoidance using a cooperative mechanism between vehicles and wireless infrastructure. In particular, we propose an infrastructure, called CISN (Cooperative Infrastructure associated with Sensor Networks), in which proper numbers of sensor nodes are deployed on each road, surrounding the intersection. In the proposed architecture, overall service performance is influenced by various parameters consisting of the infrastructure, such as the number of deployed sensor nodes, radio range and broadcast interval of base station, and so on. In order to test the feasibility of the CISN model in advance, and to evaluate the correctness and real-time transmission ability, an intersection sensor deployment simulator is developed. Through various simulations on several environments, we identify optimal points of some critical parameters to build the most desirable CISN.

• Proceedings of the KSRS Conference
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• v.1
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• pp.332-335
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• 2006

Red tide(harmful algae) in the Korean Coastal Waters has a given a great damage to the fishery every year. However, the aim of our study understands the influence of meteorological factors (air and water temperature, precipitation, sunshine, solar radiation, winds) relating to the mechanism of red tide occurrence and monitors red tide by satellite remote sensing, and analyzes the potential area for red tide occurrence by GIS. The meteorological factors have directly influenced on red tide formation. Thus, We want to predict and apply to red tide formation from statistical analyses on the relationships between red tide formation and meteorological factors. In future, it should be realized the near real time monitoring for red tide by the development of remote sensing technique and the construction of integrated model by the red tide information management system (the data base of red tide - meteorological informations). Finally our purpose is support to the prediction information for the possible red tide occurrence by coastal meteorological information and contribute to reduce the red tide disaster by the prediction technique for red tide.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.2
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• pp.9-17
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• 1994

This paper proposes Double queue threshold QLT(Queue Length Threshold) algorithm and Hysteresis effect QLT algorithm. as being DPS(Dynamic Priority Scheduling) techniques. in order to advance the processing of multiple class traffics. Also, the performance of the proposed algorithms is analyzed through computer simulations,and the priority scheduling is analyzed using a retrial queue with two types of calls. Our simulation results show that the performance of the proposed Double queue length threshold QLT algorithm is superior to that of the conventinal QLT algorithm for 2 or more classes delay sensitive traffics. Also we find that Hysteresis effecT QLT algorithm is better mechanism than that of the existing QLT for real time and non-real time traffics.

• Journal of the Korean Operations Research and Management Science Society
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• v.37 no.3
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• pp.95-116
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• 2012

The purpose of this paper is to show the effect of information sharing strategy on the supply chain performances. While traditional information sharing models assumed centralized stock information, recent supply chain practices often implement fully shared stock information, where real-time stock information is accessible on retailers. When retailers are competing with each other, this fully shared stock information may incur retailers' strategic order behaviors. Thus, this paper analyzes a simple two-level supply chain consisting of one warehouse and two identical competing retailers where the real time stock information is fully shared. The warehouse uses the traditional echelon stock policy. Under this environment the retailers' reorder decisions are derived using the order risk concept and the retailer competition mechanism is analyzed. Computational results show that the supply chain performace degradation in the fully shared stock information is quite significant, implying the importance of designing information sharing strategies in the supply chain design phase.

• 한국정보컨버전스학회:학술대회논문집
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• 2008.06a
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• pp.71-74
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• 2008

The current middleware, managing the bridges equipped whit sensor networks on real-time basis, merely processes the data collected from the sensor networks, In this study, we develop a very versatile middleware which mediates between sensor nodes and exclusive applications or web browsers. It collects and processes the data from the network. On database failures, it stores the data in a file and sends them to the database at a proper speed considering the rate of the database system when the database is restored. Lastly, in order to notice abnormality of the bridge to the operators when some problems occur in the bridge, we propose a mechanism for producing alarm signals.