• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.9A
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• pp.796-800
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• 2011

An energy-efficient multi-hop scheme based on cooperative MIMO (multiple-input multiple-output) technique is proposed for wireless sensor networks, taking into consideration the modulation constellation size, transmission distance, and extra training overhead requirement. The scheme saves energy by selecting the hop length. In order to evaluate the performance of the proposed scheme, a detailed analysis of the energy and delay efficiencies in the proposed scheme compared with the equidistance scheme is presented. Results from numerical experiments indicate that by use of the proposed scheme significant savings in terms of total energy cousumption can be achieved.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.06a
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• pp.33-43
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• 1994

It is the purpose of this paper to review the recent developments and future trends in various membrane processes, which will result in energy savings. Historically, there was a long period of academic curiosity in membrane research covering from gas separation to reverse osmosis. With advent of asymmetric membrane technology, many membrane processes proved to be energy efficient than the conventional separation methods. Thus, membrane technology has gained wide acceptance from many sectors of industry. The commercial sale of membranes is still modest compared to the major technologies, but it is one of the fastest growing industries. Recently the U.S.Department of Energy conducted a study (1) to evaluate and prioritize research needs in the membrane separation industry in order to foster and better support the deveolpment of energy-efficient new technologies. The National Science Foundation (U.S.A.) did also do a similar investigation. Both agencies have arrived neary at the same conclusion, that is, membrane separations can offer many new and alternative methods of separations that are more energy efficient than existing processes. This paper is largely based on these findings.

• Journal of Communications and Networks
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• v.18 no.3
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• pp.320-326
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• 2016

In existing literature on multiple-input multiple-output (MIMO) relaying communication systems, antenna selection is often implemented by maximizing the channel capacity or the output single-to-noise ratio (SNR). In this paper, we propose an energy-efficient low-complexity antenna selection scheme for MIMO relaying communication systems. The proposed algorithm is based on beamforming and maximizing the Frobenius norm to jointly optimize the transmit power, number of active antennas, and antenna subsets at the source, relaying and destination. We maximize the energy efficiency between the link of source to relay and the link of relay to destination to obtain the maximum energy efficiency of the system, subject to the SNR constraint. Compared to existing antenna selection methods forMIMO relaying communication systems, simulation results demonstrate that the proposed method can save more power in term of energy efficiency, while having lower computational complexity.

• International Journal of Computer Science & Network Security
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• v.22 no.9
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• pp.389-395
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• 2022

A Mobile Sensor Network is widely used in real time applications. A critical need in Mobile Sensor Network is to achieve energy efficiency during routing as the sensor nodes have scarce energy resource. The nodes' mobility in MWSN poses a challenge to design an energy efficient routing protocol. Clustering helps to achieve energy efficiency by reducing the organization complexity overhead of the network which is proportional to the number of nodes in the network. This paper proposes"EERA: Energy Efficient Routing Algorithm for Mobile Sensor Network" is divided into five phases. 1, Cluster Formation 2.Cluster head and Transmission head selection 3.Path Establishment / Route discovery and 4,Data Transmission. Experimental Analysis has been done and is found that the proposed method performs better than the existing method with respect to four parameters.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2011.04a
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• pp.116-120
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• 2011

With population growth and quality of life improvement, household energy use also has increased. Under this circumstances, consumers are increasingly required to seek for efficient ways of energy saving. However, precedent studies have largely overlooked energy consumers' consumption behavior, and particularly little research has been conducted on energy consumption or saving patterns of residents living in apartments, which account for over 50% of the Korean housing market. Therefore, this study examined apartment residents' energy use behavior according to apartment residents' characteristics in order to efficient energy use and management. To this examination, survey was conducted of housewives living in apartments in Busan, and 403 data were analyzed by the SPSS WIN 12.0 program. With respect to their energy behavior according to characteristics of subjects, it was different depending on income, housing size, age, the length of residence, and the education standard. When higher income group and larger housing size group, residents were not doing 'passive saving' and 'comfort oriented.' When younger, they were 'comfort oriented.' When well-educated, they were 'comfort oriented.' Also, with regard to the length of residence, significant difference was found. The results of this study can be utilized as effective guidelines in efficient management, policy making, and education method reflecting energy use behavior of energy users.

• 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.

• The KIPS Transactions:PartC
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• v.13C no.1 s.104
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• pp.103-112
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• 2006

Since sensor node has a limited energy supply in a wireless sensor network, it is very important to maximize the network lifetime through energy-efficient routing. Thus, many routing protocols have been developed for wireless sensor networks and can be classified into flat and hierarchical routing protocols. Recent researches focus on hierarchical routing scheme and LEACH is a representative hierarchical routing protocol. In this paper, we investigated the problems of the LEACH and proposed a novel energy efficient routing scheme, called ENTER(ENergy efficient Two-tiEr Routing protocol), to resolve the problem. ENTER reduces an energy consumption and increases a network lifetime by organizing clusters by the same distributed algerian as in the LEACH and establishing paths among cluster-heads to transmit the aggregated data to the sink node. We compared the performance of the ENTER with the LEACH through simulation and showed that the ENTER could enhance the network lifetime by utilizing the resources more efficiently.

• Journal of the Korean housing association
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• v.26 no.5
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• pp.89-96
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• 2015

This project was conducted as part of the Building America program that proposed the overall mission to achieve 30-50% reduction in existing building energy use. The purposes of this project were to analyze architectural styles and features named as archetypes of existing homes within the Great Lakes regions that include Michigan and identify the dominant type that would offer significant potential for energy-efficient retrofit. Housing archetypes were analyzed according to vintage, style, and construction characteristics in two target cities within the region. The findings from an intensive case study targeting the City of Ann Arbor established a fundamental framework for characterizing local housing archetypes and determined the dominant housing archetype that needed energy-efficient retrofit. An extended case study then conducted in Grand Rapids additionally refined this framework for the future application. This paper explained the process and data collection method to develop the framework that can be utilized by other researchers to determine the target housing types for energy-retrofit research.

• Journal of Korea Society of Digital Industry and Information Management
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• v.4 no.2
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• pp.29-37
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• 2008

Clustering allows hierarchical structures to be built on the nodes and enables more efficient use of scarce resources, such as frequency spectrum, bandwidth, and energy in wireless sensor networks (WSNs). This paper proposes a hierarchical clustering algorithm called EEHC which is more energy efficient than existing algorithms for WSNs, It introduces region node selection as well as cluster head election based on the residual battery capacity of nodes to reduce the costs of managing sensor nodes and of the communication among them. The role of cluster heads or region nodes is rotated among nodes to achieve load balancing and extend the lifetime of every individual sensor node. To do this, EEHC clusters periodically to select cluster heads that are richer in residual energy level, compared to the other nodes, according to clustering policies from administrators. To prove the performance improvement of EEHC, the ns-2 simulator was used. The results show that it can reduce the energy and bandwidth consumption for organizing and managing WSNs comparing it with existing algorithms.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.12
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• pp.5928-5947
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• 2019

Multicast Mesh based Mobile Ad-hoc NETworks (MANETs) provide efficient data transmission in energy restraint areas without a fixed infrastructure. In this paper, the authors present an improved version of protocol SLIMMER developed by them earlier, and name it SLIMMER-SN. Most mesh-based protocols suffer from redundancy; however, the proposed protocol controls redundancy through the concept of forwarding nodes. The proposed protocol uses remaining energy of a node to decide its energy efficiency. For measuring stability, a new metric called Stability of Node (SN) has been introduced which depends on transmission range, node density and node velocity. For data transfer, a weighted cost function selects the most energy efficient nodes / most stable nodes or a weighted combination of both. This makes the node selection criteria more dynamic. The protocol works in two steps: (1) calculating SN and (2) using SN value in the weighted cost function for selection of nodes. The study compared the proposed protocol, with other mesh-based protocols PUMA and SLIMMER, based on packet delivery ratio (PDR), throughput, end-to-end delay and average energy consumption under different simulation conditions. Results clearly demonstrate that SLIMMER-SN outperformed both PUMA and SLIMMER.