• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제17권8호
• /
• pp.2259-2277
• /
• 2023

We propose a probabilistic fish growth model for smart aquaculture systems equipped with IoT sensors that monitor the ecological environment. As IoT sensors permeate into smart aquaculture systems, environmental data such as oxygen level and temperature are collected frequently and automatically. However, there still exists data on fish weight, tank allocation, and other factors that are collected less frequently and manually by human workers due to technological limitations. Unlike sensor data, human-collected data are hard to obtain and are prone to poor quality due to missing data and reading errors. In a situation where different types of data are mixed, it becomes challenging to develop an effective fish growth model. This study explores the unique characteristics of such a combined environmental and weight dataset. To address these characteristics, we develop a preprocessing method and a probabilistic fish growth model using mixed data sampling (MIDAS) and overlapping mixtures of Gaussian processes (OMGP). We modify the OMGP to be applicable to prediction by setting a proper prior distribution that utilizes the characteristic that the ratio of fish groups does not significantly change as they grow. We conduct a numerical study using the eel dataset collected from a real smart aquaculture system, which reveals the promising performance of our model.

• 한국정보과학회:학술대회논문집
• /
• 한국정보과학회 2011년도 한국컴퓨터종합학술대회논문집 Vol.38 No.1(A)
• /
• pp.359-360
• /
• 2011

In this work. a new receiver-driven channel rendezvous mechanism is proposed for multi-channel communication in Wireless sensor networks (WSNs). The work is a light-weight scheduled scheme. seems to be incurring less overhead in compare to traditional common control channel based rendezvous mechanisms.

• 산업기술연구
• /
• 제29권B호
• /
• pp.127-131
• /
• 2009

This paper presents the development of smart counting system that is proper for grains with uneven unit weight or shape. This device can detect the small differences of a light beam and count the pulse from wave shape control, when the grain is going on the light screen, which is made by the light beam screen sensor. It can, different from the former conventional device, distinct the uneven grains for counting detect, by using the dedicated hardware and the software algorithm of the light sensor.

• Journal of Magnetics
• /
• 제12권4호
• /
• pp.156-160
• /
• 2007

In this paper, we analyze the errors associated with magnetic field interference for fiber-optic current sensors working in a three-phase electric system and provide a solution to compensate the interference. For many practical conductor arrangements, the magnetic filed interference may cause errors unacceptable for the accuracy requirements of the sensors. We devised a real time compensation method for the interference by introducing geometric and weight factors. We realized the method using simple electronic circuits and obtained the real time compensated outputs with errors of ${\pm}1%$.

• 항공우주시스템공학회지
• /
• 제2권1호
• /
• pp.17-21
• /
• 2008

A compact, light-weight, integrated flight control computer(IFCC) for small unmanned autonomous vehicles is developed. Its design objective is to produce an all in one avionics system which includes the navigation sensor, data link, attitude sensors and air data sensors. The initial phase of ground and flight tests are performed to verify the prototype IFCC, showing promising results. The high potential of its application is expected.

• 센서학회지
• /
• 제29권5호
• /
• pp.279-282
• /
• 2020

In this study, body pressure was quantitatively detected using built-in optical sensors, inside an air cushion seat. The proposed system visualizes the effect of the body pressure distribution on the air cushion seat. The built-in sensor is based on the time-of-flight (ToF) optical method, instead of the conventional electrical sensor. A ToF optical sensors is attached to the bottom surface of the air-filled cells in the air cushion. Therefore, ToF sensors are durable, as they do not come in physical contact with the body even after repeated use. A ToF sensor indirectly expresses the body pressure by measuring the change in the height of the air-filled cell, after being subjected to the weight of the body. An array of such sensors can measure the body pressure distribution when the user sits on the air cushion seat. We implemented a prototype of the air cushion seat equipped with 7 ToF optical sensors and investigated its characteristics. In this experiment, the ToF optical pressure sensor successfully identified the pressure distribution corresponding to a sitting position. The data were accessed through a mobile device.

• 한국인터넷방송통신학회논문지
• /
• 제10권5호
• /
• pp.293-298
• /
• 2010

유비쿼터스 센서 네트워크(Ubiquitous Sensor Network) 기술의 핵심은 저전력 무선 통신기술과 효율적 라우팅을 위한 적절한 자원할당 기술이다. 센서 네트워크에서 효율적인 자원할당을 위해서는 서비스에 따른 차별화된 자원할당 방식이 필요하다. 이를 위하여, 본 논문에서는 유선망에 사용되는 PQ와 WRR의 단점을 보완하여 USN에 적용이 가능한 스케줄러 알고리즘을 제안한다. 제안된 알고리즘은 센서 네트워크에서 각 클래스의 큐 상태를 체크하여 퍼지 이론을 적용한 제어 정책에 따라 WRR 스케쥴러의 가중치를 동적으로 할당하였다. 시뮬레이션 결과 제안된 알고리즘은 EF 클래스의 패킷 손실률에서 WRR 스케쥴러 방식보다 평균 6.5% 향상되었으며, AF4 클래스에서는 PQ 방식보다 평균 45% 향상된 결과를 보였다.

• 센서학회지
• /
• 제14권3호
• /
• pp.137-143
• /
• 2005

Research in the field of biosensor has enormously increased over the recent years. The metal-oxide semiconductor field effect transistor (MOSFET) type protein sensor offers a lot of potential advantages such as small size and weight, the possibility of automatic packaging at wafer level, on-chip integration of biosensor arrays, and the label-free molecular detection. We fabricated MOSFET protein sensor and proposed the gold-black electrode as the gate metal to improve the response. The experimental results showed that the output voltage of MOSFET protein sensor was varied by concentration of albumin proteins and the gold-black gate increased the response up to maximum 13 % because it has the larger surface area than that of planar-gold gate. It means that the expanded gate allows a larger number of ligands on same area, and makes the more albumin proteins adsorbed on gate receptor.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
• /
• pp.381-382
• /
• 2007

Recently fishing industry is interested in efficient and automated fishing implementations to reach the level of the international leading technology. One of the important device used in fishing boat is an automated electric compass that harnesses the GPS and terrestrial magnetic sensor. The electric compass is desired to be minimized in size while keeping a high effectiveness in the characteristic of a magnetic compass. This device also can be used as a heading angle sensor to construct auto-navigation system in a small size of ships. However, there exists measurement errors induced from the slope of terrestrial magnetic sensor caused by the motion of boat. In this paper, a method has been proposed removing the measurement error arising from the slope of terrestrial magnetic sensor when the ship is in motion. We have designed a sensor with two DOF(degree of freedom) and a weight to maintain the horizontality of the sensor. Through this research, the hardware has been designed and also a test has been performed. The test shows a promissory result.

• International Journal of Aeronautical and Space Sciences
• /
• 제17권3호
• /
• pp.442-453
• /
• 2016

A significant source of vibration in helicopters is the main rotor system, and it is a technical challenge to reduce the vibration in order to ensure the comfort of crew and passengers. Several types of passive devices have been applied to conventional helicopters in order to reduce the vibration. In recent years, helicopter manufacturers have increasingly adopted active vibration control systems (AVCSs) due to their superior performance with lower weight compared with passive devices. AVCSs can also maintain their performance over aircraft configuration and flight condition changes. As part of the development of AVCS software for light civil helicopter (LCH) applications, a test bench is constructed and vibration control tests and simulations are performed in this study. The test bench, which represents the airframe, is excited using a pair of counter rotating force generators (CRFGs) and a multiple input single output (MISO) AVCS that consists of three accelerometer sensors and a pair of CRFGs; a filtered-x least mean square (LMS) algorithm is applied for the vibration reduction. First, the vibration control tests are performed with uniform sensor weights; then, the change in the control performance according to changes in the sensor weight is investigated and compared with the simulation results. It is found that the vibration control performance can be tuned through adjusting the weights of the three sensors, even if only one actuator is used.