• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.7
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• pp.62-70
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• 2015

The energy of a sensor in a Wireless Sensor Network (WSN) puts a limit on the lifetime of the network. To prolong the lifetime, a clustering plan is used. Clustering technology gets its energy efficiency through reducing the number of communication occurrences between the sensors and the base station (BS). In the distributed clustering protocol, LEACH-like (Low Energy Adaptive Clustering Hierarchy - like), the number of sensor's cluster head (CH) roles is different depending on the sensor's residual energy, which prolongs the time at which half of nodes die (HNA) and network lifetime. The position of the CH in each cluster tends to be at the center of the side close to BS, which forces cluster members to consume more energy to send data to the CH. In this paper, a protocol, pseudo-LEACH, is proposed, in which a cluster with a CH placed at the center of the cluster is formed. The scheme used allows the network to consume less energy. As a result, the timing of the HNA is extended and the stable network period increases at about 10% as shown by the simulation using MATLAB.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.2B
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• pp.138-147
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• 2012

With the improvement of wireless communication and embedded technology, WSN is used at various fields. Meanwhile, because WSN is resource constrained, it is more vulnerable than other networks. To solve the security problem of WSN, we can use the traditional secure mechanism like as cryptography and authentication. But the traditional secure mechanism is not enough for all security issues that may be happened in WSN, especially attacks caused by the compromised node. So, we need the IDS as the second secure mechanism for WSN. In this paper, we propose the Specification-based Intrusion Detection Mechanism that makes LEACH, which is one of the clustering routing protocol for WSN, more reliable and safety.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.10
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• pp.50-58
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• 2013

In Wireless Sensor Network, clustering scheme is used to prolong the lifetime of WSN by efficient usage of energy of sensor. In the distributed clustering protocol just like LEACH, every sensor in a network plays a cluster head role once during each epoch. So the FND is prolonged. But, even though every sensor plays a head role, the energy consumed by each sensor is different because the energy consumed increases according to the distance to the Base Station by the way of multiple increase. In this paper, we propose a mechanism to select a head depending on the distance to Base Station, which extends the timing of FND occurrence by 68% compared to the LEACH and makes network stable.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1349-1358
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• 2009

Because of the limitation of supporting power, the current WSN(Wireless Sensor Network) Technologies whose one of the core attributes is low power consumption are the best solution for shipping container networking in stack environment such as on vessel. So it is effective to use the Wireless Sensor Network Technology. In this case, many nodes join in the network through a sink node because there are difficulties to get big money and efforts to set up a lot of sink node. It needs clustering-based proactive protocol to manage many nodes. But it shows low reliability because they have effect on radio frequency in metal obstacle environments(interference, distortion, reflection, and etc) like the intelligent container. In this paper, we proposed an improved Modified LEACH Protocol for stableness radio frequency environment. In the proposed protocol, we tried to join the network and derived stable topology composition after the measuring of link quality. Finally, we verified that the proposed protocol is composing more stable topology than previously protocol in metal obstacle environment.

• Resources Recycling
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• v.25 no.3
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• pp.11-19
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• 2016

A fundamental study to recycle a Si-Sludge and waste copper nitrate solution acid solution generated by domestic electronic industries was carried out. The waste copper nitrate solution was used as the lixiviant to leach the metals like Cu, Ca, Fe, etc. from the sludge leaving Si in the residues. The effect of reaction temperature, time and pup density on the metals leaching from the sludge was investigated. To enhance the extractability of Fe, the effect of HCl, $HNO_3$ and $H_2O_2$ introduced additionally during the leaching was also examined. Considering the leaching efficiency of Fe along with Cu, the leaching conditions comprising of 200 ~ 225 g/L pulp density and $90^{\circ}C$ temperature for 30 min were optimized. Under this condition, 98.27 ~ 99.17% Cu could be dissolved in the leach liquor with the obtained purity of Si in the residues as 98.69 ~ 98.86 %. The study revealed that the leaching of Cu contained in the Si-Sludge with the waste copper nitrate solution is a plausible approach by which the obtained leach liquor can further be treated suitably to recover Cu as the high pure value-added products.

• International Journal of Computer Science & Network Security
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• v.23 no.8
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• pp.121-136
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• 2023

Wireless Sensor Networks (WSNs) have many potential applications and unique challenges. Some problems of WSNs are: severe resources' constraints, low reliability and fault tolerant, low throughput, low scalability, low Quality of Service (QoS) and insecure operational environments. One significant solution against mentioned problems is hierarchical and clustering-based multipath routing. But, existent algorithms have many weaknesses such as: high overhead, security vulnerabilities, address-centric, low-scalability, permanent usage of optimal paths and severe resources' consumption. As a result, this paper is proposed an energy-aware, congestion-aware, location-based, data-centric, scalable, hierarchical and clustering-based multipath routing algorithm based on Numerical Taxonomy technique for homogenous WSNs. Finally, performance of the proposed algorithm has been compared with performance of LEACH routing algorithm; results of simulations and statistical-mathematical analysis are showing the proposed algorithm has been improved in terms of parameters like balanced resources' consumption such as energy and bandwidth, throughput, reliability and fault tolerant, accuracy, QoS such as average rate of packet delivery and WSNs' lifetime.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.10
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• pp.4883-4901
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• 2016

Energy efficiency in Wireless Sensor Networks (WSNs) is very appealing research area due to serious constrains on resources like storage, processing, and communication power of the sensor nodes. Due to limited capabilities of sensing nodes, such networks are composed of a large number of nodes. The higher number of nodes increases the overall performance in data collection from environment and transmission of packets among nodes. In such networks the nodes sense data and ultimately forward the information to a Base Station (BS). The main issues in WSNs revolve around energy consumption and delay in relaying of data. A lot of research work has been published in this area of achieving energy efficiency in the network. Various techniques have been proposed to divide such networks; like grid division of network, group based division, clustering, making logical layers of network, variable size clusters or groups and so on. In this paper a new technique of group based WSNs is proposed by using some features from recent published protocols i.e. "Energy-Efficient Multi-level and Distance Aware Clustering (EEMDC)" and "Energy-Efficient Multi-level and Distance Aware Clustering (EEUC)". The proposed work is not only energy-efficient but also minimizes the delay in relaying of data from the sensor nodes to BS. Simulation results show, that it outperforms LEACH protocol by 38%, EEMDC by 10% and EEUC by 13%.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.5
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• pp.107-116
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• 2011

In this paper, a traffic adaptive sleep based medium access control (TAS-MAC) protocol for wireless sensor networks (WSNs) is proposed. The protocol aims for WSNs which consist of clustered sensor nodes and is based on TDMA-like schema. It is a typical schedule based mechanism which is adopted in previous protocols such as LEACH and Bit-Map Assisted MAC. The proposed MAC, however, considers unexpected long silent period in which sensor nodes have no data input and events do not happen in monitoring environment. With the simple traffic measurement, the TAS-MAC eliminates scheduling phases consuming energy in previous centralized approaches. A frame structure of the protocol includes three periods, investigation (I), transmission (T), and sleep-period (S). Through the I-period, TAS-MAC aggregates current traffic information from each end node and dynamically decide the length of sleep period to avoid energy waste in long silent period. In spite of the energy efficiency of this approach, the delay of data might increase. Thus, we propose an advanced version of TAS-MAC as well, each node in cluster sends one or more data packets to cluster head during the T-period of a frame. Through simulation, the performance in terms of energy consumption and transmission delay is evaluated. By comparing to BMA-MAC, the results indicate the proposed protocol is more energy efficient with tolerable expense in latency, especially in variable traffic situation.

• Korean Journal of Ecology and Environment
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• v.49 no.3
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• pp.176-186
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• 2016

For several decades, lactic acid bacterium (Lactobacillus graminis: LAB) has been generally recognized as safe. To develop the pan-environmental bio-control agent, algicidal activity of the live LAB cell and its culture filtrate (CF) was examined against Microcystis aeruginosa. LAB cells perfectly lysed M. aeruginosa within 3 days, while the CF had a less effect than the live cells, approximately 78% inhibition of algal growth during a same culture period. The concentration of microcystin in alone culture of M. aeruginosa was $7.1{\mu}gL^{-1}$, but gradually increased and leach $158.5{\mu}gL^{-1}$ on 10 days. However, LAB cells clearly decreased the microcystin by $10.3{\mu}gL^{-1}$ in the same period, approximately 93.5%. CF of LAB showed a strong algicidal activity over 75% between pH 2-7, 91.3% by the treatment of proteinase K, 87.8% by below 3 kDa in particle size, and 75.3% by heat treatment, respectively. Of five solvents, fractions of CF passed through solvents diethyl ether and ethyl acetate showed an obvious algicidal activity in the algal-lawn test. Among 5 fractions purified by silica-gel TLC plate, two spots showed a most strong removal activity on M. aeruginosa. Another analysis of GC indicate that CF contained six representative fatty acids. Even though most of these substance have been known as an anti-algal substance against M. aeruginosa, oleic acid is the most effective. These results suggested that the culture filtrate or specific substances, like a fatty acids, in comparison with live L. graminis can be a successful and eco-friendly agent to control Microcystis bloom.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7541-7548
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• 2015

Wireless Sensor Networks is the technology which is used in explore role for military purposes, as well as various fields such as industrial equipment management, process management, and leverage available technologies by distributing node into various areas. but there are some limitations about energy, processing power, and memory storage capacity in wireless sensor networks environment, because of tiny hardware, so various routing protocols are proposed to overcome it. however existing routing protocols are very vulnerable in the intercommunication, because they focus on energy efficiency, and they can't use existing encryption for it, Because of sensor's limitations such like processing power and memory. Therefore, this paper propose mutual authentication scheme that prevent various security threats by using mutual authentication techniques and, Key generation and updating system as taking into account energy efficiency.