• Journal of Hospice and Palliative Care
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• v.10 no.4
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• pp.195-201
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• 2007

Purpose: As a part of the analysis of home-based cancer patients management of public health renters in cities, counties and districts across the nation, this study is to understand the degree of patient demands for that management and the degree and scope of the supply for the patient's demand. Methods: Developed the questionnaire which was constituted of degree of demand and supply for home-based cancer patient management and analyzed data centering on the frequencies and percentages by utilizing SPSS WIN 12.0. Results: The services provided through the home-based cancer patients management project include physical, emotional, spiritual and education/informative services. A survey was conducted for home-based cancer patients about these services, and its result showed that the degree of demand and supply was highest for emotional service, followed by education/informative service, spiritual service and physical service in the order of the demand-supply degree. When main items for each service were examined, it was found that: in the case of physical service, pain control was provided murk lower than its demand, while excretion disorder control and individual hygiene is provided murk more than its demand. In the case of emotional service, the degree of demand was overall higher than that of supply; spiritual service was provided appropriately to the degree of demand. Conclusion: This study examines the home-based canter patients management project of public health centers and compares and analyzes the degree of demand for patient services and the degree of services that are actually provided. The findings could be used as based data for the development of effective programs in future on the basis of actual demands of home-based cancer patients.

• Journal of the Korea Society for Simulation
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• v.15 no.3
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• pp.79-86
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• 2006

This paper proposes a new protocol to enhance the routing performance and applies our proposal to AODV (Ad hoc On-demand Distance Vector routing) protocol, which is a typical on-demand routing protocol in MANET. In general, when a route repair procedure is performed due to the transfer or failure of a node, the source node re-initiate a route discovery procedure in most routing protocols of MANET. This causes to increase the control traffic overhead largely and degrade the routing performance. The main idea of our study is to provide a methodology that can minimize the control traffic overhead and enhance the performance by initiating a route repair procedure at destination node and utilizing the previous routing information maximumly. To evaluate the performance of the our mechanism, we have performed a series of simulations. The simulations include comparisons with AODV and AODV with local repair. The simulations have been executed under simulation environments taking into account mobility speed and network site. The simulation results show that our proposal overall outperforms the existing protocols.

• Journal of Communications and Networks
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• v.13 no.5
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• pp.518-524
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• 2011

A high assurance IP encryption (HAIPE) compliant protocol accelerator is proposed for military networks consisting of red (or classified) networks and black (or unclassified) networks. The boundary between red and black sides is assumed to be protected via a HAIPE device. However, the IP layer encryption introduces challenges for bandwidth on demand satellite communication. The problems experienced by transmission control protocol (TCP) over satellites are well understood: While standard modems (on the black side) employ TCP performance enhancing proxy (PEP) which has been shown to work well, the HAIPE encryption of TCP headers renders the onboard modem's PEP ineffective. This is attributed to the fact that under the bandwidth-on-demand environment, PEP must use traditional TCP mechanisms such as slow start to probe for the available bandwidth of the link (which eliminates the usefulness of the PEP). Most implementations recommend disabling the PEP when a HAIPE device is used. In this paper, we propose a novel solution, namely broadband HAIPE-embeddable satellite communications terminal (BHeST), which utilizes dynamic network performance enhancement algorithms for high latency bandwidth-on-demand satellite links protected by HAIPE. By moving the PEP into the red network and exploiting the explicit congestion notification bypass mechanism allowed by the latest HAIPE standard, we have been able to regain PEP's desired network enhancement that was lost due to HAIPE encryption (even though the idea of deploying PEP at the modem side is not new). Our BHeST solution employs direct video broadcast-return channel service (DVB-RCS), an open standard as a means of providing bandwidth-on-demand satellite links. Another issue we address is the estimation of current satellite bandwidth allocated to a remote terminal which is not available in DVBRCS. Simulation results show that the improvement of our solution over FIX PEP is significant and could reach up to 100%. The improvement over the original TCP is even more (up to 500% for certain configurations).

• ETRI Journal
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• v.42 no.4
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• pp.585-595
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• 2020

Integration of multiple communication technologies in a smart grid (SG) enables employing cognitive radio (CR) technology for improving reliability and security with low latency by adaptively and effectively allocating spectral resources. The versatile features of the CR enable the smart meter to select either the unlicensed or the licensed band for transmitting data to the utility company, thus reducing communication outage. Demand response management is regarded as the control unit of the SG that balances the load by regulating the real-time price that benefits both the utility company and consumers. In this study, joint allocation of the transmission power to the smart meter and consumer's demand is formulated as a two stage multi-armed bandit game in which the players select their optimal strategies noncooperatively without having any prior information about the media. Furthermore, based on historical rewards of the player, a real-time pricing adaptation method is proposed. The latter is validated through numerical results.

• Proceedings of the KIEE Conference
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• 2007.04c
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• pp.119-121
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• 2007

The increment of electric power demand causes interest on new higher power system such as 42V Power Net, and furthermore necessity for development of energy storage device is highlighted recently. Owing to high efficiency and easy speed control of brushless DC(BLDC) motor, the demand of BLDC motor that has high power and low noises are increasing. Especially demand of interior permanent magnet(IPM) type BLDC with high efficiency and high power in electric motion vehicle is increasing. This paper presents the design of the BLBC motor for EHPS(Electro-Hydraulic Power Steering) in 42V system and verified the characteristics by simulation and test results.

• Journal of Computational Design and Engineering
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• v.1 no.4
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• pp.233-242
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• 2014

A magnetically levitated vehicle (Maglev) system is under commercialization as a new transportation system in Korea. The Maglev is operated by an unmanned automatic control system. Therefore, the plan of train operation should be carefully established and validated in advance. In general, when making a train operation plan, statistically predicted traffic data is used. However, a traffic wave often occurs in real train service, and demand-driven simulation technology is required to review a train operation plan and service quality considering traffic waves. We propose a method and model to simulate Maglev operation considering continuous demand changes. For this purpose, we employed a discrete event model that is suitable for modeling the behavior of railway passenger transportation. We modeled the system hierarchically using discrete event system specification (DEVS) formalism. In addition, through implementation and an experiment using the DEVSim++ simulation environment, we tested the feasibility of the proposed model. Our experimental results also verified that our demand-driven simulation technology can be used for a priori review of train operation plans and strategies.

• International Journal of Internet, Broadcasting and Communication
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• v.6 no.2
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• pp.17-19
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• 2014

Now is the applications are using WSN for environmental monitoring and surveillance applications, intelligent transportation systems, monitoring, disaster recovery, and the structure used in the field. Also, the low cost of the communication and control functions can be provided, in particular management of smart grid demand may be used in many applications. In this paper, WSN in smart grid is based on the building blocks of smart grid management system proposed for the fuzzy demand.

• Journal of the Korean Operations Research and Management Science Society
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• v.17 no.2
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• pp.91-106
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• 1992

It an inventory control system, the demand over time are often assumed to be independently identically distributed (i. i. d.). However, the demands may well be correlated over time in many situations. The estimation of reorder points is not simple for correlated demands with variable lead time. In this paper, a general class of autoregressive and moving average processes is considered for modeling the demands of an inventory item. The first four moments of the lead-time demand (L) are derived and used to approximate the distribution of L. The reorder points at given service level are then estimated by the three approximation methods : normal approximation, Charlier series and Pearson system. Numerical investigation shows that the Pearson system and the Charlier series performs extremely well for various situations whereas the normal approximation show consistent underestimation and sensitive to the distribution of lead time. The same conclusion can be reached when the parameters are estimated from the sample based on the simulation study.

• KDI Journal of Economic Policy
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• v.43 no.1
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• pp.29-52
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• 2021

The purpose of this paper is to measure the impact of the recent Korea-Japan trade dispute on the Korean economy using supply-driven input-output analysis. In July 2019, Japan announced the decision to tighten the export control of three materials which are indispensable in the manufacturing of semiconductors and electronic display panels. Japan's decision directly affects production in Korea's semiconductor and display sectors and is hence not a demand shock. For this reason, a standard demand-driven input-output analysis is not valid despite the fact that it can still be applied. The impact of Japan's decision on Korea's aggregate and individual sectors' gross output, GDP and employment were computed using both methods.

• Journal of the Korea Society of Computer and Information
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• v.25 no.12
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• pp.195-202
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• 2020

The control system for the efficiency of resource utilization in sensor network environment based on object detection and environmental sensor requires active control function which based on sensor data acquisition and transmission functions and server's data analysis. Using active rule-based mobile agent middleware, this paper proposes a new distributed control framework that reduces the load of central sensor data server in sensor network environment by implementing remote data sensing and Zigbee-based communication with server and data analysis method of server. In addition, we implemented a power-saving system prototype using active rule-based distributed control methods that applied consumer's demand and environmental variables, and verified the validity of the proposed system through experiments and evaluations in the mobile agent middleware environment. The proposed system is a system framework that can efficiently autonomously control distributed objects in the sensor network environment, and it can be applied effectively to the development of demand response service based on optimal power control for the smart power system in the future.