• The KIPS Transactions:PartA
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• v.16A no.1
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• pp.1-8
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• 2009

Ubiquitous computing requires an intelligent environment where the users do not need to be involved in the operation. The agent technology allows effective implementation of ubiquitous system, while agent platform provides efficient and stable interaction between the agents. In this paper we propose a hierarchical P2P networking approach where the messages are combined inside the agent platform and then compressed in two levels. The proposed approach capitalizes the static nature of the messages of typical context-aware applications. Experiment with an actual multi-agent system reveals that the response time and throughput are significantly improved compared to the existing scheme.

• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.1
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• pp.42-49
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• 2009

Most Vehicular Ad hoc Network (VANET) applications rely heavily on broadcast transmission of traffic related information to all reachable nodes within a certain geographical area. Among various broadcast approaches, flooding is the first broadcasting technique. Each node rebroadcasts the received message exactly once, which results in broadcast storm problems. Some mechanisms have been proposed to improve flooding in Mobile Ad hoc Networks (MANET), but they are not effective for VANET and only a few studies have addressed this issue. We propose two distance-based and timer-based broadcast suppression techniques: 15P(15percent) and slotted 15P. In the first (distance based) scheme, node's transmission range is divided into three ranges (80%,15%and5%). Only nodes within 15% range will rebroadcast received packet. Specific packet retransmission range (15%) is introduced to reduce the number of messages reforwarding nodes that will mitigate the broadcaststorm. In the second (timer-based) scheme, waiting time allocation for nodes within 15% range isused to significantly reduce the broadcaststorm. The proposed schemes are distributed and reliedon GPS information and do not requireany other prior knowledge about network topology. To analyze the performance of proposed schemes, statistics such as link load and the number of retransmitted nodes are presented. Our simulation results show that the proposed schemes can significantly reduce link load at high node densities up to 90 percent compared to a simple broadcast flooding technique.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.10C
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• pp.902-911
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• 2002

A wireless ad-hoc network is a collection of wireless mobile hosts forming a temporary network without the aid of any centralized adminstration or standard support services. Wireless ad-hoc networks may be quite useful in that they can be instantly deployable and resilient to change. In this environment, for many crucial distributed applications, it is necessary to design robust virtual infrastructures that are fault-tolerant, self-stabilized, and resource-efficient. For this task this paper proposes a scheme of maintaining robust spanning trees which are little affected by topological changes. By maintaining such a spanning tree and adapting it to the environments with frequent topological changes, one can improve the reliability and efficiency of many applications that use the spanning tree.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.927-929
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• 2011

Since DVC (Distributed Video Coding) and FRUC (Frame Rate Up Conversion) techniques need to have an efficient motion compensated frame interpolation algorithms. Conventional works of these applications have mainly focused on the performance improvement of overall system. But, in some applications, it is necessary to evaluate how well the MCI (Motion Compensated Interpolation) frame matches the original frame. For this aim, this paper deals with the modeling methods for evaluating the block-based matching cost. First, several matching criteria, which have already been dealt with the motion compensated frame interpolation, are introduced and then combined to make estimate models for the size of MSE (Mean Square Error) noise of the MCI frame to original one. Through computer simulations, it is shown that the block-based cost evaluation models are tested and can be effectively used for estimating the MSE noise.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1346-1354
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• 2018

Quality of the power system depends upon the reliability of its components such as transformer, transmission lines, insulators, circuit breakers and isolators. The transient voltage due to internal or external reasons may affect the insulation level of the components. The insulation level of these components must be tested against these conditions. Different studies, testing of different electrical components against high voltage impulses and different industrial applications rely on the international manufactures for pulsed power generation and testing, that is quite expensive and large in size. In this paper a model of impulse voltage generator with capacitive load of pin type insulator is studied by simulation method and by an experimental setup. A ten stage high voltage impulse generator (HVIG) is designed and implemented for different applications. In this proposed model, the cost has been reduced by using small and cheap capacitors as an alternative for large and expensive ones while achieving the same effectiveness. Effect of the distributed capacitance in each stage is analyzed to prove the effectiveness of the model. Different values of front and tail resistances have been used to get IEC standard waveforms. Results reveal the effectiveness at reduced cost of the proposed model.

• Proceedings of the KAIS Fall Conference
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• 2003.11a
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• pp.231-235
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• 2003

Network infrastructure has spread to an unprecedented extent and is used in various computing devices, such as smart appliances, smart phones, and embedded devices with sensors, which have all been appearing in the computing environment. To accommodate this trend, for a more intelligent service environment, the service platform needs to have abilities that facilitate the operation between services, dynamically share distributed computing resources, and manage appropriate contextual information. We have simulated a service platform to provide intelligent services using contextual information after having implemented the context management service. The context management service gathers raw contextual information from sensors and stores these in the context database. For a consistent basis of contextual information, time and location are used as the key values of the contextual information. The context management service also performs normalization to provide computable contextual information to context-aware applications. In this paper, a service platform based on Jini technology is proposed for constructing an interoperable, dynamic, and . intelligent service environment using contextual information.

• Journal of Information Processing Systems
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• v.13 no.5
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• pp.1299-1319
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• 2017

This paper presents a scalable multiple camera collaboration strategy for active tracking applications in large areas. The proposed approach is based on distributed mechanism but emulates the master-slave mechanism. The master and slave cameras are not designated but adaptively determined depending on the object dynamic and density distribution. Moreover, the number of cameras emulating the master is not fixed. The collaboration among the cameras utilizes global and local sectors in which the visual correspondences among different cameras are determined. The proposed method combines the local information to construct the global information for emulating the master-slave operations. Based on the global information, the load balancing of active tracking operations is performed to maximize active tracking coverage of the highly dynamic objects. The dynamics of all objects visible in the local camera views are estimated for effective coverage scheduling of the cameras. The active tracking synchronization timing information is chosen to maximize the overall monitoring time for general surveillance operations while minimizing the active tracking miss. The real-time simulation result demonstrates the effectiveness of the proposed method.

• The Korean Journal of Applied Statistics
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• v.31 no.6
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• pp.751-759
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• 2018

Cho et al. (Communications for Statistical Applications and Methods, 23, 423-432, 2016) introduced a risk model with a continuous type investment and studied the stationary distribution of the surplus process. In this paper, we extend the earlier analysis by assuming that additional instant investment is made when the surplus process reaches a certain sufficient level. We obtain the explicit form of the stationary distribution of the surplus process. The case is shown as an example, when the amount of claim is exponentially distributed.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.1
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• pp.939-950
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• 2021

The purpose of this research is to investigate the factors affecting Thai commercial bank users' behavioral intention towards QR code payment system via mobile banking applications. The researchers conducted the study based on quantitative research approach. Non-probability sampling method such as the quota and convenience sampling was applied as sampling technique. A self-administered questionnaire was distributed. The data was collected from 1,800 respondents living in Bangkok, who have had an experience with QR code payment system with the top-three mobile banking applications in Thailand. This study concentrates on confirmatory factor analysis and structural equation modeling as a statistical tool to examine the data, model accuracy, and influence of critical variables. In addition, the researchers applied the first-order and second-order techniques to examine the relationship between constructs. Adoption readiness and perceived risk were second-order constructs. The results reveled that compatibility has an impact on attitude towards QR code payment. Moreover, adoption readiness, compatibility, attitude, and personal innovativeness are statistically significant that impact behavioral intention towards QR code payment. The strongest antecedents of behavioral intention were compatibility, attitude, adoption readiness, and personal innovativeness, respectively. Surprisingly, perceived risk and perceived trust do not statistically have a significant impact on behavioral intention towards QR code payment.

• Journal of Distribution Science
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• v.20 no.5
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• pp.49-64
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• 2022

Purpose: This research aims to determine the quality of online store designs that make consumers who use online market board applications have the urge to make impulse buying. This research was conducted because impulse buying is the most common buying behavior. Research design, data and methodology: This research used non-probability sampling. The sample size was 195 respondents from the distribution and service industries by applying a purposive sampling technique. The data collection technique employed a questionnaire distributed online according to predetermined criteria: mobile device users who accessed the online market board application and made at least one purchase in the last six months. The data analysis method utilized was structural equation modeling (SEM). Results: The findings revealed that usability, functionality, and sociability factors affected hedonic and utilitarian search. Furthermore, these findings proved that hedonic search affected impulse buying drives. In contrast, the utilitarian search did not affect impulse buying drives. Conclusions: The usability, functionality, and sociability factors supported hedonic and utilitarian searches. Consumer information security increased consumer confidence in an online store because it was considered to protect matters related to their privacy. The hedonic search also increased impulse buying drives. Consumers prefer to use their spare time to search through online market board applications, which provide many attractive promos.