• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.3
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• pp.59-64
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• 2020

In the Paris Climate Agreement, Korea submitted an ambitious goal of reducing the greenhouse gas emission forecast (BAU) by 37% by 2030. And as one of the countermeasures, a smart grid, an intelligent power grid, was presented. In order to apply the smart grid, EMS(Energy Management System) needs to be installed and operated in various fields, and the supply is delayed due to the lack of awareness of users and the limitations of system ROI. Therefore, recently, various data analysis and control technologies have been proposed to increase the efficiency of the installed EMS. In this study, we present a measurement control algorithm that analyzes and predicts big data collected by IoT using a SARIMA model to check and operate energy consumption of public sports facilities.

• Smart Structures and Systems
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• v.13 no.3
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• pp.435-451
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• 2014

In this paper, we investigate the vibration control of multimodal structures and present an efficient control law that requires less energy supply than active strategies. This strategy is called modal global semi-active control and is designed to work as effectively as the active control and consume less power which represents its major limitation. The proposed law is based on an energetic management of the optimal law such that the controller follows this latter only if there is sufficient energy which will be extracted directly from the system vibrations itself. The control algorithm is presented and validated for a cantilever beam structure subjected to external perturbations. Comparisons between the proposed law performances and those obtained by independent modal space control (IMSC) and semi-active control schemes are offered.

• Journal of Electrical Engineering and Technology
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• v.7 no.2
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• pp.171-177
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• 2012

The autonomous microgrid is a system that is autonomously operated depending on the grid and internal load condition, without the operator's intervention. In this study, a control algorithm for the microsource and an operation algorithm for the microgrid are proposed to realize the autonomous microgrid system. In addition, a microgrid operation system based on the operation algorithm is proposed. The electromagnetic transient program is used by the proposed microsource control algorithm for simulation, and the validity of the algorithm is verified. The proposed operation system is verified based on a case study using a simulator and test devices.

• Journal of Electrical Engineering and Technology
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• v.11 no.2
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• pp.353-360
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• 2016

Series hybrid electric vehicles (SHEVs) having multiple power sources such as an engine- generator (EnGen), a battery, and an ultra-capacitor require a power control unit with high power density and reliable control operation. However, manufacturing using separate individual power converters has the disadvantage of low power density and requires a large number of power and signal cable wires. It is also difficult to implement the optimal power distribution and fault management algorithm because of the communication delay between the units. In order to address these concerns, this approach presents a design methodology and a power control algorithm of an integrated power converter for the SHEVs powered by multiple power sources. In this work, the design methodology of the integrated power control unit (IPCU) is firstly elaborately described, and then efficient and reliable power distribution algorithms are proposed. The design works are verified with product-level and vehicle-level performance experiments on a 10-ton SHEV.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12B
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• pp.1083-1096
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• 2008

This paper proposes an energy-aware path management scheme, so-called the TBP(Threshold based Back-Pressure) algorithm, which is designed for lifetime extension of the energy-constrained wireless sensor networks. With the goal of fair energy consumptions, we extensively utilize the available paths between the source and the sink nodes. The traffic distribution feature of the TBP algorithm operates in two scales; the local and the whole routing area. The threshold and the back-pressure signal are introduced for implementing those operations. It is noticeable that the TBP algorithm maintains the scalability by defining both the threshold and the back-pressure signal to have their meanings locally confined to one hop only. Throughout several experiments, we observe that the TBP algorithm enhances the network-wide energy distribution. which implies the extension of the network lifetime. Additionally, both the delay and the throughput outcomes show remarkable improvements. This shows that the energy-aware path control scheme holds the effects of the congestion control.

• Journal of Information Processing Systems
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• v.15 no.3
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• pp.593-603
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• 2019

In wearable healthcare systems, sensor devices can be deployed in places around the human body such as the stomach, back, arms, and legs. The sensors use tiny batteries, which have limited resources, and old sensor batteries must be replaced with new batteries. It is difficult to deploy sensor devices directly into the human body. Therefore, instead of replacing sensor batteries, increasing the lifetime of sensor devices is more efficient. A transmission power control (TPC) algorithm is a representative technique to increase the lifetime of sensor devices. Sensor devices using a TPC algorithm control their transmission power level (TPL) to reduce battery energy consumption. The TPC algorithm operates on a closed-loop mechanism that consists of two parts, such as sensor and sink devices. Most previous research considered only the sink part of devices in the closed-loop. If we consider both the sensor and sink parts of a closed-loop mechanism, sensor devices reduce energy consumption more than previous systems that only consider the sensor part. In this paper, we propose a new approach to consider both the sensor and sink as part of a closed-loop mechanism for efficient energy management of sensor devices. Our proposed approach judges the current channel condition based on the values of various body sensors. If the current channel is not optimal, sensor devices maintain their current TPL without communication to save the sensor's batteries. Otherwise, they find an optimal TPL. To compare performance with other TPC algorithms, we implemented a TPC algorithm and embedded it into sensor devices. Our experimental results show that our new algorithm is better than other TPC algorithms, such as linear, binary, hybrid, and ATPC.

• Journal of Communications and Networks
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• v.18 no.5
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• pp.713-724
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• 2016

Energy consumption has become a main problem of sustainable development in communication networks and how to communicate with high energy efficiency is a significant topic that researchers and network operators commonly concern. In this paper, an energy-efficient multicast algorithm in multi-hop wireless networks is proposed aiming at new generation wireless communications. Traditional multi-hop wireless network design only considers either network efficiency or minimum energy consumption of networks, but rarely the maximum energy efficiency of networks. Different from previous methods, the paper targets maximizing energy efficiency of networks. In order to get optimal energy efficiency to build network multicast, our proposed method tries to maximize network throughput and minimize networks' energy consumption by exploiting network coding and sleeping scheme. Simulation results show that the proposed algorithm has better energy efficiency and performance improvements compared with existing methods.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.2
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• pp.23-30
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• 2014

Some application of the sensor networks such as crop management must control the temperature within a proper range. The energy-efficient applications and protocols for them are needed. In this paper, we propose an energy efficient application protocol which can meet these needs. We use the concept of safety zone to manage the appropriate range of properties within our algorithm. We name our proposed algorithm "MSZ". To assess the performance of the proposed algorithm the actual temperature data was collected using the sensor node. The algorithm was implemented through programming and compared with the other algorithms. Experimental results show that the MSZ algorithm has a much better performance than that of APTEEN in terms of energy efficiency as well as has the ability of determining the status of sensor nodes with the periodical transmitting. Our MSZ algorithm can be useful in applications developments for the management of crops, fermented food and etc.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.6
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• pp.642-648
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• 2015

Recently, there have been many studies pertaining to reducing energy consumption on ships. As part of those studies, the energy consumption of ships can be reduced by understanding and controlling the varying loads, excluding fixed loads. In existing ships, engine room fans are usually operated based on the actual experience of the crew without any special guidelines. To realize energy reduction, we investigate the characteristics of engine-room fans, and we propose an energy-management system called the engine room fan control system (ERFCS) and the ERFCS algorithm. The ERFCS controls the fan speed depending on the temperature and pressure, where one to four fans are operated depending on changes in the load. In addition, the minimum rotation speed of the engine-room fan was limited to 50% to prevent the surging phenomenon, which is due to fan damage or low pressure resulting from mechanical friction or heating at low fan speeds. We develop a fan control system simulation model using LabVIEW that is based on the proposed algorithm and ISO 8861. Finally, we perform simulations to confirm that operation of the proposed fan control system is possible using only 46.4% of the power required by the existing method.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.1
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• pp.8-13
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• 2015

In this paper, a simple algorithm is proposed to estimate wind speed and direction which can significantly improve the landing performance of an unmanned parafoil. The proposed algorithm is applied to flight test data along with other known algorithms and the results are compared and discussed. The proposed algorithm shows comparable performance while it can still be applied to the parafoil under control.