• 한국멀티미디어학회논문지
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• 제17권8호
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• pp.977-987
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• 2014

Many of the recent performance evaluation of clustering schemes in wireless sensor networks considered one sink node operation and fixed sink node location without mentioning about any network application requirements. However, application environments have variable requirements about their networks. In addition, network performance is sufficiently influenced by different sink node location scenarios in multi-hop based network. We also know that sink location can influence to the sensor network performance evaluation because of changed multipath of sensor nodes and changed overload spots in multipath based wireless sensor network environment. Thus, the performance evaluation results are hard to trust because sensor network is easily changed their network connection through their routing algorithms. Therefore, we suggest that these schemes need to evaluate with different sink node location scenarios to show fair evaluation result. Under the results of that, network performance evaluation results are acknowledged by researchers. In this paper, we measured several clustering scheme's performance variations in accordance with various types of sink node location scenarios. As a result, in the case of the clustering scheme that did not consider various types of sink location scenarios, fair evaluation cannot be expected.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 춘계학술대회
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• pp.509-512
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• 2015

본 논문에서는 유압 실린더내의 피스톤 위치를 측정하기 위한 정전용량 센서(Capacitive Sensor) 구조를 연구하였다. 기존에 유압 실린더 내 피스톤 위치 측정을 위해 인덕티브(Inductive) 방식을 응용한 LVDT(Linear Variable Differential Transformer) 센서가 사용되고 있으며, 높은 정확도를 갖지만, 고가이며 구조적으로 복잡하다는 단점이 있다. 본 논문에서는 이러한 단점을 극복하기 위한 방법으로 유압실린더 내 최적화된 구조를 바탕으로 여러 가지 비접촉 정전용량 센서 구조 방식을 연구하였다. 실험을 통하여 본 논문의 제안구조를 사용하면 유압 실린더 내 피스톤 위치측정이 가능함을 확인하였다.

• 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.

• 한국기계가공학회지
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• 제18권1호
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• pp.116-121
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• 2019

The LVDT (Linear Variable Displacement Transducer) type sensor used for the existing ship's steering gear is simple on / off that does not perform proportional control operation to the control & unloading device. When the main spool is located at both extremes, It is reflected in the price by using an expensive sensor for import. In this paper, the Hall Effect Sensor is applied to Hydraulic Locking Alarm to analyze classification rules, structure, characteristics and operation principle of valves, and research on localization development in terms of cost reduction. The comparative analysis of the existing prototypes and the cause analysis of the problems were carried out, and the structural analysis showed satisfactory results within the allowable stress range. In addition, it was verified through experiments that the actual operation is realized by applying the actual developed product, and it was confirmed that the load on the maximum value exceeds the allowable maximum load even in the case of the universal tensile test in preparation for the departure of the rod casing.

• Journal of Biosystems Engineering
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• 제34권6호
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• pp.434-438
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• 2009

This study was conducted to design an cone penetrometer type impedance sensor that can measure soil water content in realtime. The best width between electrical probe was determined by 5 mm. For optimization about realtime application device, linear regression analysis was applied between soil water content and impedance signal. It was concluded that proper combination of excitation frequency, impedance parameter, and model would provide acceptible performance of a soil waler content sensoe. Best model was obatained at a 36.5 MHz with |Z| as a predictor variable, with a coefficient of determination of 0.96 (RMSE=1.35, RPD=4.98).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1165-1168
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• 2001

The effect of sensor faults in DTC based induction motor drives is analyzed and a fault detection problem is treated. An adaptive gain scheduling observer is proposed for the design of DTC controller and a fault detection system. The observer provides not only the estimate of stator flux, a key variable in DTC system, but also the estimates of stator current, rotor speed that are useful for fault detection purpose. Simulations for various type of sensor faults are performed to evaluate the performance of the overall control system and the proposed sensor fault detection scheme.

• 한국산업융합학회 논문집
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• 제18권3호
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• pp.167-172
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• 2015

In this paper, we propose a new approach to design and control a smart gripper of robot system. A control method for flexible grasping a object in partially unknown environment was proposed, where a proximate sensor detecting the distance between the fingertip and object was used. Based on the proximate sensor signal the finger motion controller could plan the grasping process divided in three phases. The first step is scanning process which two first joints were moved to mid-position of the detected range by a state-variable feedback position controller, after the scanning was finished. The contact force of fingertip was then controlled using the detection sensor of the servo controller for finger joint control. The proposed grasping planning was tested on rectangular bar.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1884-1886
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• 2002

At present, the variable sensors are applied to detect PD pulse signals, UHF sensor, AE sensor and etc. In this paper we used the Rogowski sensor to detect PD pulse signals in air. We did performed test simulation and niddle to plane electrode structure for PD source. We compared Rogowski sensor with conventional type PD detector to detect discharge signals in air.

• International Journal of Computer Science & Network Security
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• 제22권2호
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• pp.131-138
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• 2022

Soft sensors are used to anticipate complicated model parameters using data from classifiers that are comparatively easy to gather. The goal of this study is to use artificial intelligence techniques to design and build soft sensors. The combination of a Long Short-Term Memory (LSTM) network and Grey Wolf Optimization (GWO) is used to create a unique soft sensor. LSTM is developed to tackle linear model with strong nonlinearity and unpredictability of manufacturing applications in the learning approach. GWO is used to accomplish input optimization technique for LSTM in order to reduce the model's inappropriate complication. The newly designed soft sensor originally brought LSTM's superior dynamic modeling with GWO's exact variable selection. The performance of our proposal is demonstrated using simulations on real-world datasets.

• 한국안전학회지
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• 제3권1호
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• pp.7-13
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• 1988

The oxides in perovskite type, $LaMO_3$ (M=Ni, Cr, Fe, Co), compared with gas sensors which have been used, were synthesised and then examined sensor response comparatively in order to make a thick film gas sensor having a good gas selectivity, durability and simple manufacturing. The oxides in perovskite type, $LaFe_{1-x}O_3$ (x=0.2, 0.4, 0.6, 0.8), which a part of Fe was replaced with Co, were examined with regard to their electric resistance with variable temperature and sensor response for carbon monoxide gas.