• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권6호
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• pp.1706-1727
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• 2023

Under Water Sensor Networks (UWSN) has gained attraction among various communities for its potential applications like acoustic monitoring, 3D mapping, tsunami detection, oil spill monitoring, and target tracking. Unlike terrestrial sensor networks, it performs an acoustic mode of communication to carry out collaborative tasks. Typically, surface sink nodes are deployed for aggregating acoustic phenomena collected from the underwater sensors through the multi-hop path. In this context, UWSN is constrained by factors such as lower bandwidth, high propagation delay, and limited battery power. Also, the vulnerabilities to compromise the aquatic environment are in growing numbers. The paper proposes an Energy-Efficient standalone Intrusion Detection System (EEIDS) to entail the acoustic environment against malicious attacks and improve the network lifetime. In EEIDS, attributes such as node ID, residual energy, and depth value are verified for forwarding the data packets in a secured path and stabilizing the nodes' energy levels. Initially, for each node, three agents are modeled to perform the assigned responsibilities. For instance, ID agent verifies the node's authentication of the node, EN agent checks for the residual energy of the node, and D agent substantiates the depth value of each node. Next, the classification of normal and malevolent nodes is performed by determining the score for each node. Furthermore, the proposed system utilizes the sheep-flock heredity algorithm to validate the input attributes using the optimized probability values stored in the training dataset. This assists in finding out the best-fit motes in the UWSN. Significantly, the proposed system detects and isolates the malicious nodes with tampered credentials and nodes with lower residual energy in minimal time. The parameters such as the time taken for malicious node detection, network lifetime, energy consumption, and delivery ratio are investigated using simulation tools. Comparison results show that the proposed EEIDS outperforms the existing acoustic security systems.

• Journal of Ecology and Environment
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• 제48권1호
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• pp.24-31
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• 2024

Background: Honey from different geographical origins can have distinct characteristics due to variations in the floral sources available to stingless bees in different regions. The most abundant stingless bee for meliponiculture in Thailand is Tetragonula pagdeni. However, only a few studies about the properties of honey from a different origin were carried out. The objective of this study was focused on a comparative study to evaluate the melissopalynological, physicochemical, antioxidant activities, and total phenolic contents (TPCs) of stingless bee honey produced by T. pagdeni from different parts of Thailand. Results: Fifty honey samples were collected from five locations, and the physicochemical properties of T. pagdeni honey samples are acidic (pH 3.02-4.15) and have a high water content (18.42-25.06 %w/w), which is related to the regions of meliponary. Melisopalynological analysis reveals the predominant pollen from Melaleuca quinquenervia, Cocus nuciferca, Nephelium lappaceum, Salacca wallichiana, and multiflora honey. All honey samples were analyzed for their TPC and 2,2-diphenyl1-picrylhydrazyl radical scavenging activity. The results show that all samples had high TPC and antioxidant activities with a strong correlation (p < 0.05). Conclusions: The data from this study indicates the importance of geographical origin, which links physicochemical properties, phenolic compounds, and functional characteristics to their floral. Besides, the floral sources and harvesting location affected the properties of stingless bee honey. Our results identify Melaleuca honey as a promising source of phenolic content and antioxidant activity that can be used as a functional food, as well as multiflora and Cocus honey. However, further studies are required to characterize the phenolic compound and its biological potential, which could be a stingless bee honey biomarker and quality control, simultaneously with the physicochemical analysis.

• 전기학회논문지P
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• 제63권1호
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• pp.34-39
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• 2014

In cognitive radios, secondary users can use the spectrum exclusively allocated to a primary wireless system if the secondary users detect the spectrum in idle states. Because the secondary users can utilize the idle state of the spectrum, the utilization rate of the spectrum can be improved. The idle states can be detected by using secondary users' sensing schemes. However, the wireless channel environment where secondary users perform the spectrum sensing is not very friendly to secondary users because the signal-to-noise ratio of the received primary signal is very low. Hence, cooperative sensing scheme where more than one secondary user take part in the spectrum sensing is generally used in cognitive radios. In this paper, we investigate the cooperative sensing performance for machine-to-machine communication devices operated by batteries with limited energy. In general, the energy consumed for the spectrum sensing increases as the length of the sensing period and the number of cooperative sensing nodes. Accordingly, even though the total amount of the consumed energy is the same, an energy allocation methodology how to distribute the energy to the sensing period and sensing nodes can achieve the optimum sensing performance, which is numerically analyzed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권9호
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• pp.3151-3168
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• 2021

Internet of Things (IoT) connects several objects with embedded sensors and they are capable of exchanging information between devices to create a smart environment. IoT smart devices have limited resources, such as batteries, computing power, and bandwidth, but comprehensive sensing causes severe energy restrictions, lowering data quality. The main objective of the proposal is to build a hybrid protocol which provides high data quality and reduced energy consumption in IoT sensor network. The hybrid protocol gives a flexible and complete solution for sensor selection problem. It selects a subset of active sensor nodes in the network which will increase the data quality and optimize the energy consumption. Since the unused sensor nodes switch off during the sensing phase, the energy consumption is greatly reduced. The hybrid protocol uses Dijkstra's algorithm for determining the shortest path for sensing data and Ant colony inspired variable path selection algorithm for selecting active nodes in the network. The missing data due to inactive sensor nodes is reconstructed using enhanced belief propagation algorithm. The proposed hybrid method is evaluated using real sensor data and the demonstrated results show significant improvement in energy consumption, data utility and data reconstruction rate compared to other existing methods.

• 한국환경복원기술학회지
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• 제11권4호
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• pp.12-23
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• 2008

This study has a purpose of setting applicable ecological environment plan items when establishing city development plan. To achieve this purpose, multiple methods of data gathering, documentary surveys, and questionaries research were used in this study. The main findings of this study can be summarized as follows; 1. The appliance of ecological environment plan is appropriate to apply before the establishment of development plan. 2. The items applicable to ecological environment plan establishment step by step is the following. First, it is necessary to prepare the environment improvement plan and ecology restoration on the stage of assigning the area. Second, on the stage of planning development plan, it is required to set the restoration plan of ecological resources and step by step ecological environment plan. Third, on the stage of plan implementation, it is required to set the maintenance guide on ecological environment. 3. The planning items of ecological environment plan are "geographical features and soil", "water resource", "wind resource", "green resource", "circulation of resource", "usage of nature energy" and "habitats", etc. 4. To apply ecological environment plan to the planning of development, it is necessary to specify the clear concepts and specific plan. 5. This study is limited to select generalized planning items and later on, it is necessary to develop detailed planning contents.

• Structural Engineering and Mechanics
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• 제67권1호
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• pp.93-104
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• 2018

The seismic behavior of reinforced concrete (RC) short columns with limited transverse reinforcement is investigated in this paper through an experimental program. The experimental program consists of four small-scale RC columns with an aspect ratio of 1.7, which are tested to the axial failure stage. The cracking patterns, hysteretic responses, strains in reinforcing bars, displacement decomposition and cumulative energy dissipation of the tested specimens are reported in detail in the paper. The effects of column axial load are investigated to determine how this variable might influence the performance of the short columns with limited transverse reinforcement. Brittle shear failure was observed in all tested specimens. Beneficial and detrimental effects on the shear strength and drift ratio at axial failure of the test specimens due to the column axial load are found in the experimental program, respectively.

• 한국지하수토양환경학회지:지하수토양환경
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• 제25권4호
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• pp.1-6
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• 2020

Recently, ex-situ remediation technologies has been emerging to clean up contaminated soils mainly because the in-situ techniques have limited applicability and technical difficulties in relatively small contaminated sites. Accordingly, implementation of off-site treatment and disposal have been continuously increased in soil remediation and restoration projects in Korea. However, in many cases, reclaimed soil is still not properly recycled or reused. Therefore, there is an urgent need to document the current status of soil management practices in soil remediation projects in the nation. This study presents a survey of soil contamination status and remedial approaches in Korea based on soil cleanup projects completed in 2015 - 2019, and proposes the possible options of the recycling or reusing the reclaimed soils under compliance with related regulations. The results of the soil survey showed soil contamination was most severe in gas stations, industrial facilities, and military areas. The major types of pollution were related to the petroleum-contaminated site (TPH and BTEX) with 77.0% occurrence in all the contaminated sites. The reclaimed soils were mostly reused as a ground filling-up soils in industrial facilities (60.0%) and warehouses (37.0%).

• 한국전자통신학회논문지
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• 제18권4호
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• pp.609-616
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• 2023

무선 네트워크 환경에서 센서들은 전원 공급을 위해 상시 전원이 연결되어 있는 것은 아니기 때문에 센서들에게 공급되는 에너지원인 배터리의 수명은 한정되어 있다. 따라서 네트워크 수명을 연장하는 다양한 연구들이 진행되어 왔으며, 효율적인 에너지 사용을 위해 계층기반 라우팅 프로토콜인 LEACH(: Low-energy Adaptive Clustering Hierarchy)가 등장하였다. 하지만 데이터 송신 시 전송거리의 제곱만큼의 에너지 소모가 이루어지기 때문에 융합된 데이터를 싱크 노드에 직접 전송하는 LEACH 프로토콜은 에너지 소모가 크다는 제한사항을 가지고 있다. 본 논문에서는 이러한 제한사항을 개선하기 위해, 매 라운드마다 클러스터 헤드들이 싱크 노드와의 상대적인 거리 계산을 통해 클러스터 헤드 간 체이닝 연결되는 멀티 홉 전송으로 전송거리를 최소화할 수 있는 알고리즘을 제안한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2514-2518
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• 2003

The KAERI Spent Fuel Remote Technology Development (SFRTD) Department is developing the remote maintenance and repair equipment, which is used in a hot cell in an intense radiation field, as part of a project to develop the Advanced spent fuel Conditioning Process (ACP). Although several mechanical master-slave manipulators (MSMs) is mounted on the hot cell wall, their reach will be limited and cannot access areas for all the ACP equipment maintenance. A Bridge Transported ServoManipulator (BTSM) has been designed to overcome the limitation of access areas that is a drawback of MSMs for the ACP equipment maintenance. The BTSM system consists of four components: a transporter with telescoping tubeset, a slave manipulator, a master manipulator, and a remote control system. The BTSM system has been designed by Solid Edge that is a 3D computer-aided design (CAD) software, except for the remote control system. The master manipulator and the slave manipulator are kinematically similar in design, except for the handle and the tong, respectively. The manipulators have 6 degrees of freedom (DOF) plus the jaws motion. The transporter has traveling, traverse, and hoisting motion to position the slave manipulator.

• 한국전자통신학회논문지
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• 제4권1호
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• pp.20-24
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• 2009

센서 노드는 제한된 에너지를 가지고 동작한다. 대부분의 경우에, 에너지가 고간된 배터리를 교체하거나 재충전하는 것은 바람직하지 않거나 불가능하다. 따라서 MAC프로토콜 디자인에서 에너지 소모를 줄이는 것은 매우 중요한 문제 중 하나이다. 하지만, 센서 응용이 지연에 민감할 경우, 지연이 매우 중요한 요소이고, 이 지연은 에너지 소비와 트레이드오프하게 된다. 따라서 본 논문에서는 에너지 소모를 줄이고, 낮은 지연을 얻을 수 있는 MAC프로토콜을 제안한다. 이 프로토콜은 DSMAC을 기반으로, 동적으로 경로 사이의 상대적인 buffer의 패킷의 양에 따라서 duty cycle를 변경하게 된다.