• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.7
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• pp.1-8
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• 2011

Vehicular Ad-hoc Network (VANET) is a special form of Mobile Ad-hoc Network designed to provide communications among nearby vehicles without communications infrastructure. Some characteristics in VANET environment such as high mobility, dynamic topology and selfishness of nodes can cause degradation of network quality. In this paper, we propose an adaptive incentive/topology control scheme to improve network quality in VANET by stimulating real time data forwarding and reporting changes of network topology. In the proposed scheme, an incentive suggested by the source node is updated in real time simultaneously with data transmission to stimulate real time data forwarding. In addition, when the order of the nodes in the path is changed, nodes which report the changes of network topology will get an additional incentive. By computer simulation, it is shown that the proposed incentive/topology control scheme outperforms the conventional schemes with respect to data delivery time and data delivery ratio.

• The KIPS Transactions:PartC
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• v.11C no.1
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• pp.99-108
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• 2004

In this paper, the performance of switched ethernet networks with different topologies as an industrial control networks is analyzed. The switched ethernet eliminated data collisions on the network and can be used to transmit real-time data. While the amount of data on the network is small compared to the computer networks, the industrial control networks require the real-time data delivery. In this paper, we analyze and compare the network performance of switched ethernet networks with linear and tree topologies whether they satisfy the real-time data delivery requirement needed to be used as the industrial control networks.

• Korean Management Science Review
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• v.21 no.3
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• pp.101-113
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• 2004

In the rapidly propagating Internet based electronic transaction environment. the importance of real time order confirmation has been more emphasized, In this paper, using data mining techniques, we develop intelligent operations decision model to allow real time order confirmation at the time the customer places an order with required delivery terms. Among various operation plannings used for order fulfillment. mill routing is the first interface decision point to link the order receiving at the marketing with the production planning for order fulfillment. Though linear programming based mathematical optimization techniques are mostly used for mill routing problems, some early orders should wait until sufficient orders are gathered for optimization. And that could effect longer order fulfillment lead-time, and prevent instant order confirmation of delivery terms. To cope with this problem, we provide the intelligent decision model to allow instant order based mill routing decisions. Data mining techniques of decision trees and neural networks. which are more popular in marketing and financial applications, are used to develop the model. Through diverse computational trials with the industrial data from the steel company. we have reported that the performance of the proposed approach is effective compared to the present heuristic only mill routing results. Various issues of data mining techniques application to the mill routing problems having linear programming characteristics are also discussed.

• Journal of KIISE
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• v.44 no.10
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• pp.1062-1070
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• 2017

Real-time transmission studies in wireless sensor networks propose a mechanism that exploits a node that has a higher delivery speed than the desired delivery speed in order to satisfy real-time requirement. The desired delivery speed cannot guarantee real-time transmission in a congested area in which none of the nodes satisfy the requirement in one hop because the desired delivery speed is fixed until the packet reaches the sink. The feature of this mechanism means that the packet delivery speed increases more than the desired delivery speed as the packet approaches closer to the sink node. That is, the packet can reach the sink node earlier than the desired time. This paper proposes an improved real-time transmission by controlling the delivery speed using the temporal gain which occurs on the packet delivery process. Using the received data from a previous node, a sending node calculates the speed to select the next delivery node. The node then sends a packet to a node that has a higher delivery speed than the recalculated speed. Simulation results show that the proposed mechanism in terms of the real-time transmission success ratio is superior to the existing mechanisms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.7A
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• pp.706-714
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• 2010

In wireless sensor networks, real-time data delivery schemes typically achieve a desired delivery speed by performing one-hop lookahead. Recently, to reduce the deadline miss ratio against the desired delivery speed, a study has proposed a real-time routing protocol based on proactively performing two-hop lookahead. However, the study might cause heavy message exchange overhead and high computing complexity to carry out obtainment of two-hop neighborhood speed information in the entire sensor nodes whether data are delivered or not. Moreover, although multi-hop lookahead provides the least deadline miss ratio, due to the restriction from the overhead and the complexity, the recent study merely adopts the two-hop lookahead manner. In this paper, we propose a novel real-time routing protocol that adopts on-demand neighborhood multi-hop information obtainments only around data forwarding paths. Simulation results prove that the proposed routing protocol offers better performances with respect to deadline miss ratio, total communication costs, energy efficiency, and network lifetime.

• The KIPS Transactions:PartA
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• v.10A no.6
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• pp.715-722
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• 2003

Monitoring is used to see if a real-time system provides a service on time. The target of monitoring is not only an interior system but also a remote system which is located in the remote network. Monitoring needs data store to monitor data from each system. But a data store should be designed on the considerations of time constraints and data accessibility. In this paper, we present an architecture of XML-based data store and network delivery. XML-based data store is based on XML which is a standardized data format. So any platform which supports TCP/IP and HTTP can access data in the data store without any conversion. The XML-based delivery architecture is designed to reduce the time of data access and delivery. In addition, some experiments were tested to provide the timing guideline to be kept by a real-time system which uses the architecture presented in this paper. The architecture of XML-based data store and delivery designed in this paper can be used in the domains of remote real-time monitoring and control.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.247-250
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• 2006

Integrating a GPS based vehicle navigation system and the latest optimal algorithms, this research aims to develop a real-time decision support platform for concrete plant to provide the optimal solutions for ready mixed concrete delivery. The platform includes fleet tracking system, simulation and optimization tools, and visual interface which is useful to monitor delivery progress, to obtain crucial historical and real-time data for simulation, and to improve the efficiency of the plant operation. This paper presents configuration of the system and performance evaluation based on operational data.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.4
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• pp.16-21
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• 2002

This paper refer to the trade-off between delivery frequency and amount between supplier and discountstores. Discountstores prefer frequent delivery of small amount because of limited storage space, while suppliers prefer less frequent delivery of large amount in order to save transportation cost In this paper we propose a heuristic algorithm to determine the amount of order and the delivery frequency which decreases the expected length of stockout. We also evaluate various order policies for vendor managed inventory system using simulation with real data.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06d
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• pp.291-296
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• 2008

Wireless network technologies are becoming more widely used in industrial environment. The industrial communication system requires a real-time delivery of messages. The sensors periodically senses the physical environment and wants to deliver the data in real-time to the sink. This paper proposes a real-time protocol for periodic messages on wireless sensor and actor networks to be used in industrial communications. The proposed protocol delivers the data message using the shortest path from the source and the nearest actor. The protocol considers the energy consumption by reducing the number of broadcast messages during flooding. We have evaluated the performance of the proposed protocol using QualNet simulator. The simulation results show that the data messages have been delivered in real-time and the number of broadcast messages is reduced from 90% to 35% compared the existing protocols.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.177-178
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• 2005

Wireless 1394 over IEEE802.15.3 must allow a data reserved for delivery over a wired 1394 network to be delivered over an IEEE802.15.3 wireless network through bridging IEEE 1394 to IEEE802.15.3. Isochronous transfers on the 1394 bus guarantee timely delivery of data. Specifically, isochronous transfers are scheduled by the bus so that they occur once every $125\;{\mu}s$ and require clock time synchronization to complete the real-time data transfer. IEEE1394.1 and Protocol Adaptation Layer for IEEE1394 over IEEE802.15.3 specify clock time synchronization for a wired 1394 bus network to a wired 1394 bus network and wireless 1394 nodes, which are IEEE802.15.3 nodes handling 1394 applications, over IEEE802.15.3. Thus, the clock time synchronizations are just defined within a homogeneous network environment like IEEE1394 or IEEE802.15.3 until now. This paper proposes new clock time synchronization method for wireless 1394 heterogeneous networks between 1394 and 802.15.3. If new method is adopted for various wireless 1394 products, consumer electronics devices such as DTV and Set-top Box or PC devices on a 1394 bus network can transmit real time data to the AV devices on the other 1394 bus in a different place via IEEE 802.15.3.